Rather than jump into what 'some people' are or aren't going to do or how they're going to perceive reality, let's just leave it alone and assume the 'other guy' is just a passionate fan like you rather than some kind of rabid zealot who defines his existence by how many people like or dislike a video game.
As to the points you suggest in the rest of your post, those are all pretty good reasons. To your second point, cooldown management also extends to weapon swapping; do you swap to your second set to use a skill knowing you won't be able to switch back for 5 seconds or do you just make do?
And of course, that's a mechanic that professions can play with; the Warrior has the "Weapon Master" trait that reduces the cooldown on weapon swapping (at least according to the GW2 wiki which is admittedly outdated). So there's some room customization in there and we haven't actually seen the final version of traits yet.
Environmental weapons are in that category too. I saw a Guardian elite ability from the Beta Footage called "Tome of Wrath" that changes the first 5 skills to some high damage/low cooldown abilities, but forces the player to remain stationary if they want to use them (it lasts about 20 seconds). You can see that here;
http://www.youtube.com/watch?v=7crErSlSmak&hd=1&t=3m50s
They also have a "Tome of Courage", but I haven't seen the exact description for it yet (though I would guess it's more support than damage).
And who knows what other skills are going to be added before release? They've established this new rule ("The first 5 slots are weapon-based and do not change") and have shown mechanics in previous builds that bend those rules ("Okay, but "Trait X" changes it a little". Who's to say that they won't have stuff later in the game that
breaks those rules ("Trait Y" completely changes the skill in slot 3).
We just don't know That's pretty much the end of every discussion there.
The problem Retro,
is that the line of thinking that other-games-did-it-like-this-so-thats-the-right-way-to-go-about-it. After all, playing it safe is what killed a lot of other games. dynamic events worked less good in Tabula Rasa(dont know if you played that) and probably also rift(didnt play that) and for sure in warhammer - it's not that dynamic events are not well done, but they were playing it safe by also offering the standard... the standard mmo mechanics to not upset all the MMO gamers who are afraid of change, or afraid of change they can't perceive.
I know GW2 will have significant problems. I expect it. I expect people to get angry over how the cash shop will evolve over the years, and I think the game will be compromised in other ways by going full MMORPG without a fee. maybe in services, maybe in latency, maybe in resource management or something, but everything has offsets.
It's dangerous to have a playerbase (or listen to a playerbase) who think they are more expert at the game than those who are making it. Particularly when those people are perceiving things through a monitor, but not with proper hands on through a long time of testing.
In fact this is one of the most interesting things about GW2 (for me at least). Lots of people seem so horrible conditioned by other games, that they wouldn't know how to play it. In this great talk;
http://www.gdcvault.com/play/1013691/Designing_Guild_Wars_2_Dynamic_Events
The developers are describing how their testers wouldn't "get it". They didn't know how to go out and explore - The conditions from past game had inserted a mantra about being told were to go, and what to do. Breadcrums had been obligatory, and just exploration had been reduced to pure time of waste.
Exploration is not time efficent. And what if you run into enemies that will kill you because they are not your level? That's less productive than going to a traditional quest hub and complete 40 quests and call it a day.
My point is, that this probably also translates to combat. How can you remove energy in the game? It created so much depth! < This is just an assumption, that a person would have because he/she is not used to NOT having it.
Sometimes rules and obstructions just create more problems. In games like WoW, it's fine because you're looking at your bar, and your enemies bar all the damn time. That's what that is.
I see mana/energy removal as a big positive because it puts more creativity into it. With Mana a system you're basically being allowed to be able to fire of abillities (from your entire pool) for a certain amount of time. Not having mana, but just relying on cooldowns, puts more emphasis on the skills themselves, and create a more high risk / high reward system - if you fire of skill 4 as a Warrior with a certain weapon and it's some AOE, and you missed your chance to use it correctly - you missed your chance. instead of doing it with mana when you can just go 4, 4, 4, 4, ...(mana depleted) 1 1 1 1 1 1 1 4 4 4 (mana depleted) 1 1 1 .. instead you can change to your other weapon - 5 new skills, pop up the other AOE.
it means fewer combat abillities of the same time in exact order, but it means more using ALL of your 10 weapon skills across the two weapon sets.
If you look at this thread you can see lots of posts about being a greatsword mesmer, or a longbow ranger. that stuff is probably the mentality of other games, but not guild wars 2.
if you think about it, It's almost like that having two weapon sets is a smaller form of the dual class system from GW1.
Particularly if you consider that healing/self support is in every class (monk/rit was such a popular secondary class in gw1) it makes sense, that subscribing to a weapon set, is almost like its own sub class, as it has its own skills and own chance of specialization.