A lot of us have adjusted to new AST (and a lot haven't...). But general opinion still seems to be that 3.0/4.0 AST was better. Hopefully we can have something like that system back in 6.0. But, there were serious problems with 3.0/4.0 AST. Could we have a new old AST, that fixes these problems?

Yes!

Using the old card system as a starting point, make the following changes:
Balance: 10% damage buff
Bole: 20% damage resist buff
Spear: 10% crit buff
Arrow: 10% direct hit buff
Spire: 10% physical damage buff
Ewer: 10% magic damage buff
The Arrow change will prevent the card from messing up people's rotations by buffing attack speed. The Spire and Ewer changes will mean that there are no more useless cards. In fact, they will be as good as Balance in parties with the right composition. And even in casual parties with all physical/ranged DPS, they can be used on tanks/healers for some damage buff.

On top of that, remove Expanded Royal Road; a 5% damage buff to the whole party was too powerful, buffing everyone is less interesting than having to choose who gets our beloved Balance. Also, give us a long-CD, out-of-combat ability that gives two Balances and Extended/Enhanced Royal Road, so that nobody has to waste time with pre-pull card-fishing.

This revised card system will make RNG management more forgiving, but still allow for optimization by skilled players.
Only 1 card won't give any damage buff (Bole); depending on party composition, 1/3 or 1/2 of the cards will give a full 10% damage boost; you won't have to fish for Expanded Royal Road, because it won't exist. But we will still have to know which jobs benefit more from crit or more from DH, and we'll have to decide if it's worth it to give Ewer to the crappy BLM, or reroll and hope we get a Balance or Spire to buff the killer SAM... even if we risk getting a Spear or Arrow or Bole instead.

In addition to this just being a better system than 5.0 AST (opinions vary, of course...) it remains true that nobody asked for the old card system to be completely replaced. Even if the replacement is just as good, it still represents a fundamental break with the trust of the players to gut a unique job with a devoted player base. Of course, we would have to gut new-AST to restore old-AST, but it doesn't seem to be nearly as loved by the player base as old AST. And with a new healer job likely coming out in 6.0, it can take inspiration from the best elements of new-AST, while old-AST is restored to its former glory. So give us back our old job. Pretty please, Yoshi-P?


PS. Can we also get back Time Dilation and the buff extension on Celestial Opposition? The other fun part of AST was double-extending three HoTs on the tank, and then spending the next 20 seconds instant-casting Gravity on dungeon trash.