Gotta keep in mind that developing something takes time and "throwing more money at it" doesn't make things actually go that much faster. Also I'm not much into crafting, so I won't list much of it.

Anyway, here's my take :

x.0 (Expansion release)

- Any of the new system features shown at FanFest
- MSQ (won't go into the specifics of how to improve it, but more voice acting and more varied quest design in a nutshell)
- The 8 dungeons and 3 trials are fine, if we wanted to improve it, maybe Final Boss EX could be in here already, having a fight for accessories, a fight for armor and a fight for weapon.

x.01/x.05

- Normal and Savage raids, I think the delayed schedule is fine
- PVP Update and season (reworks, map can be later), put rewards of past expansion's series into the trophy crystals shop (or, if you really want to drip feed it, sequence it : 6.1 rewards unlocked in 7.1, 6.2 in 7.2, etc)
- Unreal 1 (having the feature disabled 4 months is not great)
- Hunt : have group hunt bills that work like Treasure Hunts mobs : you track it somewhere and make it spawn for your group.

x.1 :

- If Final Boss EX is in .0, have the trial series start here with the first EX of the series
- If Final Boss EX on this patch, have the story of the trial series start here as a sort of teaser, maybe with a nice instanced battle
- MSQ with a dungeon
- Alliance Raid 1 (optional : make the gear upgradable like tome gear, creating new BiS and builds)
- Allied Society 1 (combat)
- Custom Deliveries 1
- Unreal 2
- Anything PVP
- x.11 : Ultimate 1 (delaying it one week after patch is a good call)

x.15 :

- Savage unlock (optional : story quest for the raid, if it benefit the story's pace and content)
- Tomestone cap raise
- Chaotic 1
- Relic step 1, tied to exploratory zone with optional farming methods
- Exploratory zone 1, or if too much to handle for the devs at this pace, have an introductory questline like suggested for the trial series, it was done well with Bozja (even if Memoria EX was kinda wack)
- Any serialized questline (Hildibrand, Tataru, etc)
- Housing updates
- Variant/Criterion 1, have gearing options tied to Criterion, making 4 ways to have potential BiS/build options (optional : create a Variant Roulette with funny modifiers that apply if no first timers are in the instance)

x.2 :

- MSQ with dungeon
- Trial series + EX
- Savage tier
- Optional : alliance raid story quest (same idea as for savage)
- Unreal 2
- Allied Society 2 (gathering)
- Anything PVP

x.25 :

- Relic step 2
- Exploratory zone 1/Exploratory zone update or expansion
- Questlines follow-up
- Crafting/gathering zone (like Ishgard Resto or Cosmic Exploration)

x.3 :

- MSQ with dungeon and EX if end of storyline
- Trial series EX or story quests with instanced battle
- Alliance Raid 2
- Allied Society 3 (crafting)
- Custom Deliveries 2
- Unreal 3
- Anything PVP