I disagree on the depth. Either it meant that you had to hold off on skills (same as cooldowns), are forced to bring an energy management skill (takes up space), or you'd try to be clever and use energy destruction on enemies (which is a lot like giving them cooldowns).
No.
Energy, as implemented in Guild Wars, was a universal resource, which cooldowns are not. This made it easy to quantify, which cooldowns are not - and the fact that it could be quantified meant that not only was 'Energy management' an entirely new avenue of gameplay, but so was 'Energy denial' - both of which are no longer even
possible to explore in Guild Wars 2.
(It's also kind of disingenuous to paint Energy Management as 'taking up space'. Lots of energy management actually synergized quite well with other skills - Channeling as a cover enchantment, as probably the easiest example.)
It also allowed a player the option to expend all of that resource in a short burst, either by blowing through their skill bar (cooldowns alone supports this), or by repeatedly using a skill with a short cooldown but high energy cost (cooldowns alone
do not support this). Powerful skills with
short cooldowns were one of the most interesting aspects of the original Guild Wars. So were powerful skills with
low Energy costs. Both were only possible because of the dual mechanics of Energy and cooldown. Skills in Guild Wars 2 must be balanced based
only on their relative strength versus the amount of time it takes before they can be used again. Skill balance in Guild Wars 1 had three dimensions; now it has two. There is, quite literally, less depth available to the designers than in the first game.
Energy also allowed for the existence of tactics like the focus swap, alternating between equipment that gave +5 Energy and equipment that gave +15 Energy, but -1 Energy Regeneration - which gave rise to 'hiding' Energy, which was one of the coolest emergent mechanics in Guild Wars. That is now gone.
It's not hard to figure out why they
wanted to remove Energy from the game. Energy was a thorn in the side of the game's designers and balancers right from launch, with nO (and others) running builds that tripled up on "Fear Me!" while half the casters took Energy Drain. It certainly makes their job easier if they can just remove such a vital mechanic from the game entirely. But that doesn't mean that they
should have, and it's undeniably removed many of the mechanics, explicit and emergent, that gave Guild Wars 1 its identity compared with other RPGs. Maybe they replaced it with something that makes up for some or all of those losses, and maybe they didn't - but they
are losses to the depth of the gameplay, and they've really got their work cut out for them if they're trying to replace that depth with other mechanics.
