In XI - as a WHM, I had to carefully watch my party health bars, factor in cast times, think about threat (hate, enmity, whatever) whilst at all times keeping my party alive. If i failed in this, players lost a pile of exp. Big penalty, big pain. As a result, i focussed on my job and on managing the various elements of my role. Threat management was the most difficult challenge and it took time to perfect my role. As a BLM, similar story but I also had to think about chaining which would sometimes require me to start a cast, before my party had even finished their routine. THis required focus, attention and effort.
In WoW, as a Priest - i just spammed the cure button on the tank. As a mage, i just spammed firebolt on the tanks target. Sometimes I would have to CC but generally it was so easy this wasnt necessary.
Im sorry - I liked WoW and XI, and I am enjoying XIV so far. THey are different games with a different target audience. WoW will suit everyone, XIV a niche audience who really want the challenge, but please dont say that WoW is just as difficult - it simply isnt true and makes you look a little silly.
Everytime I see a FF vs Warcraft argument it is the same 3 issues beaten to death:
How easy/hard it is to level
How easy/hard it is to do play your role
How easy/hard it is to get drops
The leveling argument has been blown away by abyssea. It is now much easier to level to cap in FFXI and it will probably stay that way. It was actually just as easy before abyssea doing summoner or black mage burn groups. It is now easier to level in FFXI.
All of what you described about your duties as a healer in FFXI apply to WoW except exp loss. If you were spamming your heals and nukes in WoW then either you were horribly undergeared, you had an amazing tank but most likely some combination of the two. I can't speak on priest, but as a mage I could easily rip aggro off of any good tank if I wasn't minding my threat. I don't see how you found your role in FFXI as a BLM any more challenging or engaging than a mage in WoW. I did basically the same five things all the time. Rest, sleep adds, ele debuff, nuke, stun and run. PvE mages in WoW is relatively the same. Drink, sheep, decurse, nuke, counterspell and blink. Again, same old same.
Drops in these two games are different for several reasons. In FFXI it is totally acceptable to wear gear you could equip as many as 50 levels ago(Peacock charm anyone?). In many situations this gear was actually better than what you would have available at your current level. The reason is that FFXI doesn't scale nearly as much as WoW does. In FFXI you start with about 50 hp and max out just under or above 2k depending on your job. In WoW you start maybe around 150 but increase upwards of 40k depending on class, maybe more.
The other reason is content. WoW adds raids and endgame content way more frequently than FFXI does. You progress through gear as you progress through content. Not only that, but the gear is actually useful as a set. The bonuses provided by gear in FFXI were so situational that I would have pieces of gear in my inventory that were incredibly useful despite the fact I might only cast a few times a day, once a week. The bonuses provided by sets of gear in WoW affected how you played your class immensely.