I don't think the problems are unfixable. Steepening the PDIF curves (and/or extending the caps, if they're currently an issue) would make attack *and* defense more important, which would be a big step in the right direction. Heck, even adjusting exp to pull players away from the low-VTs would increase the need for acc and atk somewhat.
Anyway... if the same slot that gave 5% haste could give 30 acc, then yeah, acc gear would be just as much of a problem. But it doesn't. The numbers matter. (Arguably being able to cap acc so easily at high levels *is* a problem, and high level mobs need more eva to compete. At least that might help with the multihit WS... But it's overshadowed by haste IMO.)
I think they should impose a much tougher haste cap than you suggest, something like 40% for melee timer and 20% for recasts - maybe even less. Once you have the amount of haste you need, then you can equip for other stats. (For the same reason, I wouldn't except Hasso - it would still give you room to equip more non-haste gear, in addition to its acc and str benefits.) Ideally I'd combine this with the adjustment that increases the influence of atk/def, so players would immediately have something else to gear for.
Alternatively, all haste could work like DW delay reduction, with TP gain per hit calculated off the adjusted delay rather than the base delay, so it would improve your DoT (and recast timers), but not your TP gain rate (for that you'd need acc or Store TP). It would still be a good stat, but not TEH ULTIMATE (outside of WS). This would also reduce the flood of infinite TP that high level melees swim in, which would help job balance issues.
Radical solutions, I know. But I think the problem is big enough to demand them. Tiny tweaks aren't going to bring back tanking, hate control, or nuking as desirable aspects of a party, let alone make Kirin a challenge again and DEF tanking viable on the mobs that are challenging right now.
And to return to TM's comment: if they designed this game pretty well initially, but then wrecked it in an expansion, what stops them from wrecking the hypothetical next one too? How many years of play do you want to invest in *that* game before it gets taken over by a few blatantly overpowered strategies that SE refuses to rein in? If they haven't learned to bite the bullet and *fix things dammit*, and let the whiners go to hell, then they won't do it on the next game either.
It's an impressive testament to SE's ability and effort that the game remains fun to play despite these obvious balance issues. But it would still be better if they fixed them.


Defeated: Maat, Divine Might, Fenrir, Kirin, Cactrot Rapido, Xolotl, Diabolos Prime, Kurrea, 9/10 Dynamis Bosses (missing Tav), Promathia, Proto-Ultima, Proto-Omega, 4 Jailers, Apocalypse Nigh
RDM75, PLD75, DRG75, COR48
Windurst Rank 10, Bastok Rank 9, ZMs & PMs Complete, AUMs Complete, First Lieutenant, Brass Wings of Service, Nyzul Floor 8