I'll be honest when I played I got super side tracked by housing so I didn't get to that much end game (which is probably why I toddler about here sometimes saying SE needs to look at that game's housing and change their current system into FC Garrison project - a big fat long term group project, WS Housing was THE BEST system I've ever seen). Anyway lol, the second point you make is where a lot of the fun of runes/relics (WoW's ability materia basically), enchants, glyphs, set bonuses, ability affixes, passives, trinkets, etc, etc littered in examples and proven in other MMORPGs to work and imo are great fun because they take what you've been doing for the last 100+ hours and tweak it.
Everyone has made legitimate points that while developers and players sometimes make it seem like you have "over 200 different choices" its more like 3 - the other ones will get you in trouble once you're in real content, but the point is you have THREE different styles of playing the thing you love playing. Its not about abandoning a job you love, its about changing up slightly what you love so its still fresh. Also would like to add you could be aboslutely goofy and not get in trouble in a lot of content in WoW, people only started to care in content that was actually moderately challenging - so you could still do what you thought was fun for some portions of content, and then in the more end game stuff you still had 2 to 3 choices.
Which feels great~ Heck, even when it doesn't "change" the rotations - it doesn't give you "3" different choices, but just makes their effects different, it's still great fun to see how you can incorporate that change and feels fresh on the last bit you've been playing around with. I remember making an on hit hunter for a short while way back when, although it was actually OP enough that Blizzard nerfed it lol, I had like 4 on hit effects and a double hit sword - basically looked like I was a rogue but I also had a pet lol.
What Ogulbuk was saying though I think is that SE could still be linear growth and make things simple on player's, because the newest gear would always have the best or at least the best in combination so you'd always know what you want to collect next - the ability affix idea works both in linear and horizontal ideas. As I said before I personally dont want to see years worth of horizontal because I'm a casual poop (used to play WoW hardcore lol), but I would like shorter term horizontal options. Like primal gear not immediately killing the one previous to it.
I'm not saying it has to be talent trees, or item bonuses, but these changes to what you love and not saying "stop playing what you like to get a different feeling" are awesome. I love sphere grids and a FFX meets FFIX could be interesting, but I fear the aspect of collecting items might make people less desired if they haven't for example collect Ifrit's Brand from the primal fight 2,000 iLvLs ago lol. I imagine it'd just be much easier to balance if they added it to the items themselves like many other major MMOs do. For both a materia based system or the FFIX/X example it may help to just let you sell them on the MW as well - so people can choose to do old content or not (anyway, strictly based on items would be the literal easiest to balance and manage for players and devs).
Still want to see a sphere grid just because they're cool but I think Duelle's suggestion for a aesthetic merit system would function better for that, so people still have something to look forward to at max and gain some neat aesthetic options.