I think that the most important thing that the Essentials missing is the Gen V pokémon. I know that they haven't good backsprites, but I guess that this is better that nothing. After this, completed all Gen IV/V effects (moves, abilities and items).
Hi. Yes. This. Please. <3
Although, I would actually advise prioritizing completing the old gen content over adding the new Pokemon. This is just my personal preference, but were I heading this project, I would rather be able to say, "Okay, we have everything through Gen IV done and done, but nothing from Gen V yet" than "Okay, we have some of the Gen IV/V content, but a bunch of it probably isn't totally functional." Similarly, that's my preference as a game developer.
Besides, we can continue using add-ons like P-Sign's to put in Gen V Pokemon and it's a close-enough fix for having the Pokemon themselves. But we can't make an add on for the utility of moves/abilties/etc. Well, not easily anyway.
But yes, regardless of which comes first, Gen V Pokemon, or utility effects of... things... this is absolutely my highest priority. I come from a competitive battling community; I want to be able to deliver to them the same battle experience they've come to expect, and I can't do that if half of the new moves/items/etc don't work.
I'll get round to prettying up and posting my "To Do" list, so everyone can at least see what I've written down. You can then take some of the notes and work on them yourselves, and turn Essentials into an actual community project, if you like.
I actually did this on my own website too, and it's worked fantastically. I think it's a great idea. If you could even get as specific as which abilities might need to be scripted in, then members might be able to contribute snippet-by-snippet (I'm remembering a topic I saw here where somebody posted their script patch for the Regenerator ability- not sure if made it into the main release).
Regardless, maybe not through twitter, but even if there was just somewhere where you said what you were working on, I would definitely appreciate that, and it would help me to plan my development accordingly. For instance, not two days before v7's release, I got to the Game Corner of my game, and then I realised that Essentials didn't have a Slot Machine yet. So, I designed the Game Corner and a couple other quick menial games around the premise that the slot machines were broken. I even made Trainers (not just NPCs) complain about them being broken. Then v7 released, and was like, HI HAVE SOME SLOTMACHINES and I was like OKAY :D but then I realised I needed to redo the Game Corner entirely. If I had known you were working on those, I could have just designed the corner as planned knowing that it would be updated shortly.
I know some of the changes I make will break older savegames (most notably the last release), but it'd be much harder to cater to them with backwards compatibility than to just improve things. I don't even try to support older versions.
From a gamedev point of view, yeah, we can just debug ourselves to where we need to be. However, what I'm worried about is my players. In order to keep a constant audience, I'm releasing rather short, rapid demos of my game. I released my first demo telling everyone, yeah, you can keep your save files between updates. So, I saw some of them soft-resetting/etc to get Pokemon with the natures/stats/whatevers that they wanted for long-term play. One of my members spent an hour and a half catching a Surskit with the right gender/nature. Then Essentials itself updated to v6 the next day, and I had to be like, okay guys, jk, for the next update only you can't keep your saves. They were bummed, but understood. I figured that was just a one time thing.
Now, v7 did the same thing, and thank god I hadn't released again yet after telling them, but I mentioned that saves -would- have had to been cleared again, and now I'm starting to get people saying that they'd rather not play the demos if their save is going to be cleared between every update. So, I am a little worried about this as a developer.
To play my own Devil's Advocate, sure, these people will still play the game when it's finished, but, in the mean time playing the demo was almost instantly a huge-community booster on my site, and the people who couldn't play or chose not to were kind of left out. I would like to be able to safely include everyone. And, worst case scenario I can just include kind of a 'default' save file with each update. But, that still doesn't permit that same level care that the players might otherwise put into the game (as in, hour/half for a surskit level-of-care) when they feel secure they won't lose their own progress. Now, I know that making things backwards compatible is extremely difficult. I know the progress is necessary over sticking to the old code. I don't really expect you to put those hours just for this reason. I'm just giving you the two-cents from beyond the developers' side.