What if something like the following happened?
1. Auto-attack implemented.
2. TP done away with.
3. All moves that required TP now have a 4-5 second individual cooldown to prevent spamming.
4. Maybe add a basic personal combo system; i.e. TP move X increases the damage of your TP move Y by 10% for 5 seconds after use or using fire spells on a monster makes it 10% weaker to water spells for 5 seconds (ala FFXI ancient magic).
I definitely feel that the combat system itself needs more inter-working mechanics built into it (like the 4th item on the above list hints at). They've currently tried to accomplish this, uniquely, through the Battle Regimen system, which isn't necessarily a bad system because it rewards good group cohesion and team-work... however, the actual combat tasks carried out by INDIVIDUAL party members in order to accomplish this are still inherently boring!
I've noticed alot of MMO's (at least from my personal experience) deal with this by using secondary systems to add measured complexity, depth, interest (through customization), and power (or the appearance thereof) to an otherwise simple ******* of core abilities. The good news is that Final Fantasy XIV already has the systems in place to accomplish all of these: a robust Armoury system with nearly unending potential for future improvement (I mean this positively), and the Guild Mark system (which is somewhat reminiscent of WoW's "talent" system).
However, the problem with both of these is that there simply isn't alot of great content filling them out. While the class system offers great potential in regards to personal customization, there's not alot of unique or interesting class-specific mechanics... it seems like most of the time I'm just leveling an extra class I don't really want to just to be able to "Do more damage if your next attack lands at all!" There is some harmony between classes of the same general role, but it lacks profundity.
On a side note, adding Auto-attack might make the combat seem a little more lively, but it wouldn't truly fix the big issues with the combat itself (I foresee several hours of DVR space vanishing in my near future!). Additionally, this sudden yearning for the return of Auto-attack is probably remediable with better combat/spell animations in general (I'm looking at you, FLARE and TRUNKSPLITTER-copy00035!)
From my perspective, the Battle Regimen system is a good idea, but there needs to be more individual input/thought going on under the surface. Personally, I'd like to see something more along the lines of the "personal combo system" quoted above.. but to maintain harmony with the Battle Regimen system, maybe include a couple of ability sequences per class (ex: THM casts Bio, Scourge, Shadowsear within 5 secs of each other, unlocks X Spell that can be used in a Battle Regimen... or casts another sequence to get Y spell... then all group members initiate Battle Regimen mode and use their unlocked abilities to achieve a Battle Regimen effect). Basically it's like adding a Battle Regimen within a Battle Regimen (so you can Battle Regimen while you Battle Regimen :3 ). Additionally, you could buy more spell sequences at your local Guild, and possibly introduce the option to purchase Guild-specific Battle Regimens through Faction reputation standing.
Just some thoughts