That's my review. Thanks for coming!
Oh, OK; I'll provide actual reasons.
First Stated Obstacle: Administration would be unmanageable-
The writer argues that because the EU takes forever to do simple things an interstellar emprie would be too difficult to rule.
His Solution: Instantaneous communications and really centralized government. Maybe implants so debates are superfast.
Why this is wrong: In Real Life the planet Earth has had a few empires that were larger than the EU and ran quite smoothly, thank you. The Spanish Empire controlled more than 1/8th of the world's land in the 16th Century and was much more efficient than the Black Legend would have you believe. The Achaemenid Empire covered 6% of the world and controlled an incredible 44% of the world's population in the 6th Century B.C! The Achaemenids lasted 220 years and their empire was son efficient and stable that their core concepts have been copied by other empires throughout history.
All without instantaneous communications.
The key is de-centralization. As a matter of fact, the entire point of the traditional monarchy/aristocracy system so familiar in Europe, Asia, etc. is that it is very good at generating efficient leadership hierarchies at the small, medium, large, and gigantic levels. Local issues are dealt with by local rulers (barons) and as issues become larger and more complicated higher levels of authority, many of which are also local!, kick in. There may even be a system, group, etc. to provide oversight.
In a fair number of the largest pre-modern empires issues as serious as wars would be dealt with and settled before the central authority even knew that they had existed. And yet, from the Persians to the Mongols to the British, there was no real weakening of the ultimate authority of the central ruler.
And the dire need for fast communications is also a little off. Look at the longest-surviving corporate (in the older meaning of the word, 'formal group activity') human endeavor - the Catholic Church. The Church uses a structure akin to the traditional feudal one (or vice-versa) and uses a concept called Subsidiarity to guide how things work: Subsidiarity boils down to 'make all decisions as far down the hierarchy and as locally as possible'. Regions of the Church cut of from Rome for years, even decades, not only survived but flourished during lack communications but had very little difficulty in submitting to Rome once contact was reestablished.
These reasons are why so many Space Operas have barons and kings!
Second Stated Obstacle: Accomodations Would Be Complicated-
Having even humans from different levels of gravity would complicate things
His Solution: Point this out and mention how you'd have to accommodate different people.
Why it bugs me: Why mention something as an obstacle when it is not really an obstacle? I mean, sure - mention that you have to do it. Star Trek did it a few times. It was sometimes a plot point in Babylon Five. The Sector General short stories and novels are ALL ABOUT 'hey - aliens are different'. The number of science fiction stories that overcome this 'obstacle' by just mentioning that you must put a little effort into it are legion and, in the end, this is like claiming 'writing about America has an obstacle because some people need ramps for their canes.'
Third Stated Obstacle: Warfare Would Be Impractical-
The author makes a few arguments against interstellar war: battles aren't very exciting; you can't take over a planet; there is no reason to fight interstellar wars because there will be plenty of resources.
His Solution: Copy Iain Banks or have little to space in your space opera.
Why this is wrong and it bugs me: First, a lot of war is fought at extreme ranges with targets represented as dots on a screen now. Battle robots have been in use since the Vietnam War!
Yes, really. The Aegis System uses what are essentially defensive battle robots.Now, I don't know about you, but I have noticed a few conflicts over the past few decades even though a ton of combat is really remote and very abstract with things like cruise missiles, UAVs, etc.
Note: The Russian flyovers of an American ship amused me, but the pearl-clutching over 'attack runs!' amused me more. The pilots were letting the ship see the planes weren't armed. In contemporary combat a plane attacking a ship wouldn't ever be in sight of the ship - they would fire ASMs for miles and miles away.So vast distances, robots in battles, dots on a screen - none of that even makes sense as an objection to war.
As far as taking over a planet, that depends. The idea of militarily attacking a planet being impossible and someone exploiting that assumption is a huge plot point in the book Dorsai!, for example.
As for how you could do it in at least on fictional setting with relatively low number of troops and without glassing cities, I wrote up a little something on that topic about, oh, 14 years ago. In the end it can take a lot fewer troops than you think to secure a nation and that would be true of a planet, too.
For example, in 2003 the population of Iraq was about 23 million people and they had an army of about 375,000 troops. The nation was seized by about 380,000 troops in about 40 days. Not 'totally pacified', but 'the previous government and military were effectively removed and key positions were controlled by invaders'.Personally, I don't think the ability or of invaders to conquer a planet matters as much as the fact that if an outside for can project enough force to be capable of at least some orbital bombardment a planet can be no less than isolated and in effect blackmailed into surrender. In short, if you can annihilate entire cities at a time with rocks a planet is going to have to win or lose in orbit.
As for the idea that abundant resources will mean the end of war?
Wars are, yes, sometimes fought over resources. But more often they are not. Ideology, religion, self-determination, revenge, and other factors are causes for war. The Great Siege of Malta was not about resources; the Balkans Wars of the 1990's were about groups of killing killing and dying to become part of smaller, weaker, poorer nations. There are very literally hundreds of real life examples that show than many wars, especially high-intensity ones, are not about resources.
Fourth Stated Obstacle: Trade Would Be Unnecessary-
The writer states that the vast resources of space combined with the sheer costs of transport would render trade moot.
His Solution: Rare materials and economies of scale.
Why this bugs me: His 'obstacle' and his 'solution' are called 'contemporary economics'. The Silk Road was hideous expensive - yet it ran for 1,500+ years! Why? Rare materials.
Right now the United States is in a manufacturing boom (yes, really) yet a majority of consumer goods are made in other locations and shipped large distances to be sold in the US. Why? Economies of scale.
Anther factor he missed: art. Africa, Europe, South and Central America, Asia, and the Indian sub-continent have multiple film and music production centers, some of extremely high quality. Yet American movies and music are imported to these nations both draining cash from local economies and stunting local businesses. Why? Perceived artistic merit.
To me this entry isn't about an obstacle it is just 'try to make your economics at least semi-realistic'.
Fifth Stated Obstacle: Energy Production Would Outmode All Conflict-
The writer essentially just repeats obstacles #3 and #4.
His Solution: Don't do that.
Why this bugs me: It is just a repeat of items #3 and #4.
In fairness, I have been thinking about these topics for almost 40 years (since I picked up the Traveller LBBs just before I saw Star Wars) and writing about SF world building for longer.
My science fiction worldbuilding aid Sea of Stars has been a Silver Pick on RPGNow since 2002 (hint, hint)!Why does it bug me, really?
Simple - the author made a classic mistake of thinking he was discussing worldbuilding but actually just telling us his own assumptions and opinions. We all do it, but it needs pointing out.