I actually like the condense of SMN and believe it should be done even more*, but continue to add more features at the same time (and I do think the complexity of SMN is a bit late, move some stuff up sooner lol). I think the PvP template is interesting, though of course for PvE you need more- and each button ideally being condensed and useful. Sort of an expansion on the MOBA concept (so instead of 40 buttons that do one thing, or a MOBA being 4 buttons that do 8 things you've got like 16 that do 30 interesting things, and most of those 16 being pressed decently often).
*Though I know not everyone likes to work with a smaller hot bar, to me... personally.. a huge hot bar is not what makes something fun, I would be much happier with the same features in less buttons (or maybe more features, and in less buttons). So I'm not suggesting all jobs have to have the same thing done, since I do believe sometimes a job should have a quirk just for those types of players like "oh that's the 15% harder to play DD, with 0.5% more damage, because some people are masochists" etc lol. I'm not into pulling the carpet on people, just stating my preference in not having to have four full hotbars because a lot of abilities could be combined but weren't "because because".
I do wish there was more elements of uniqueness for jobs. One I've tried suggesting for a while now that is fairly innocent is roleplay strictly related additions. For example Dragoon being able to jump higher than other jobs in areas they've unlocked flying. It's balanced to content design (wont ruin MSQ progression), impactful to the concept that you can jump high, and doesn't impact something like ultimate which needs very tight balance. There are a lot of things like this that could help separate each job. Something I feel WoW does much better than FFXIV. That said I don't like how in WoW you can't do everything on one character, like you can't be a crafter of all the crafts- very annoying (imo), so given FFXIV's job design I feel such serious negative impacts of differences is even less because if you wanted to jump high.. "just play dragoon" and also "you're making a big deal out of something that doesn't impact your invitation to difficult content, aka.. "why"..".
Differences that go beyond that are nice of course, but more difficult if you're trying to make very sharply tuned balance at the same time. Like when Paladin got repeat button press atonement I was like "aw man I don't want fel cleave". Now the special effect is really cool on confiteor though (so the art design offsets the gameplay lol).
WoW definitely has significant differences between some jobs, and within the specs themselves sometimes which is very cool - but it's also fairly common to have a garbage spec that no one wants to see you on because it does actually just pull large amounts of aether through a garden hose. I read that in the new expansion WoW is making alts even friendlier closer to the point that an alt is almost like FFXIV job changing system (not quite, but ish), and if they improved their balance (and stop making certain specs consistently bad lol), that could pose an interesting competition to FFXIV. Not saying anything for certain yet, because the expansion is not even out so we're all on hot air but I'm hoping FFXIV is ready to answer the call for improved competition (potentially).
Two ideas that I have when watching paint dry.. that would be far more dangerous, maybe to think about for a new/different game, but allow significantly larger differences in jobs would be:
a) Jobs have two components, the wild very role play designed job with differences as wild as how you actually progress content. Like one job might just approach content entirely different. The easy example being perhaps Blue Mage levels by learning spells. All jobs have their design based on what is both thematic and fun but only on a basic level ensuring balance (which means never purposefully make one job way better than another, and hope each job has a moment to shine, but don't' destroy a functional and fun pile of jobs because another job's concept doesn't perform as well in that concept). THEN also having a more PvP / savage / ultimate build which is made to be highly balanced (with some quirks still naturally), with probably the same sort of reduced number of buttons but with content that is extremely demanding to replace the lower buttons. Once you can echo content you can enter it with either form (the PvP version attempting to take the best notes and themes to not make it feel like two separate jobs but rather a distillation of the wild and loose form). Because most content the wild form will be in wont be hyper difficult even jobs that are unoptimized for the situation can still 'win', but everyone is going to be in a much stronger state of asymmetry.
b) Move a lot of customization into some other new concept, to keep value and fun in leveling, but make gearing and gaining 'combat' levels fairly easy- such that you design the game to actually expect players to change for situations. Might even allow players to change jobs in some content. Huge levels of care needed to ensure that the solution to every problem isn't "black mage burn" though, as was a classic when balance was a bit off in FFXIV (1.0) and FFXI (sometimes). In this situation somehow the stats need to be more separated from the classic end goal of glamours, so everyone is working for the cool new things, but somehow at the same time it isn't a HUGE pain in the chocobo when you hear "no red mage" because you've easily got three other options to come as. Jobs are more asymmetrical but it's also less taxing to expect a player to know and have multiple jobs leveled (and perhaps might even be a requirement for some content).
My own wish in one hand and something in the other though would be adding far more roleplay elements that don't impact balance in every way that is fun and interesting as much as possible for all jobs, and then adding more asymmetry than is currently present but still try to get everyone within a general expectation of value. Due to this... savage and ultimate would have moments where your job isn't as desired.. and.. that sucks ;/... Perhaps there can be an auto balance system that takes participation rates for jobs and increases the bonus for having one of that job in your party. So if your job is the least likely to be picked then it'll have the highest bonus. Would be interesting to see if players try to manipulate that system though lol.