What I'd like to see/what I hope:
-Desukan being Ground/Ghost (or vice versa) with the obvious move... Curse. I also hope if it doesn't have an evolution it has good stats to make up for the "assumed" low HP taken from the video.
-At least 150 new Pokemon. There doesn't have to be more, but I hope no less.
-At least a portion of evolutions for older Pokemon. (I want to see some added love for Kangaskhan and Pinsir) Sure maybe their stats -competitively are fine- but they could pull a Scizor and just redistribute stats or add typing to help said Pokemon.
-Nuzlocke rule system, download and more.
Have a system (I doubt it'd be perfect with an introduction into the fifth gen but it could be improved in the future) with the obvious rules and the option to create rules and clauses/exceptions to made up rules to make a Nuzlocke run that is impossible of being "not followed in the rules."
The only problem people have with this is "What if I want to catch ___ ?" "What if a shiny appears on a route I already caught a Pokemon on/etc." Well that's where the clause/exceptions come in to make it so you can catch them. They'd just be stored in a "Dead Box" same with "What if I fail and have to restart" you can make a clause that allows you to select Pokemon/objects/etc. for trade to another version or you could just have Nuzlocke run + (like New Game +)
On the download idea, similar to putting your save on the website with some of the new additions, you could download a specific set of Nuzlocke rules (like ____ of the day) to try a new experience in Nuzlocke. While allowing you to pass your own on to friends and whatnot.
I would hope there is no limit to rules (maybe a 50 rule max considering I run on standard Nuzlocke 39 rules with clauses and specific exceptions: keeping the standard rules unchanged.)
-Complete type chart. (Fire/Water, Fire/Grass, Dragon/Ice, etc.) Except for maybe pure Flying.-Not to start an argument on the subject of a "characteristic element"
-Egg differences. (Atlhough that video may have shown evidence of this with that Koromori egg (?)
-IV's made less luck based. Changed but still affected in the same way. Or at least shorten the total amount added to a stat to about 10 +.
-Abilities that are basically the same as Intimidate, Pure Power, etc. For Special Attack. Also, I'd like to see a Speed Boost ability for other stats. (Except for Defense (s), and Evasion.
-Changes to the Type chart (My only complaint is Poison isn't SE against Normal and Fighting. Along with a few resistance problems such as why Ice doesn't have resistance against Dragons. )
-Grass type buffs. Sure they're doing better than a few other types, but most of the time each gen a Grass type falls down to UU or progressively lowers in competitive by being outdone by a majority. (Example every Grass starter in their origin generation is like OU but by being outclassed Post origin generation they drop lower and lower.) Subseeding or not.
-Easier nature system in breeding.
-Item that levels or boosts a Pokemon to level 100. Takes at least one month to recharge. Obtained post E4.
-Buffs to bad attacks. (Rock Smash IMO should have 75-80 BP with 100% chance of def. lowering by at least one stage . Maximum of three stages to prevent brokeness)
-More ability improvements like Sturdy has recieved or added effects. (Speed Boost=1 Turn Solar Beam without Sunny Day requirement?)
-More Eeveelutions. Ground type "Terraeon." Dragon "Feybraneon." and the like.
-Removed items brought back. (Berserker Gene) + more items with more effects.
-More TM's, Move Tutors, and more. (I'd like to see 100+ TMS)
-Items to boost stats of weak Pokemon that need it. (So something like Smeargle wouldn't recieve a boost. )
-Nintendo character cameos in Battle Subway/Frontier or whatever else may be in.
-Keep Voltorb Flip (or add another similar game) but add purchasable coins back in English version/etc.
-Make Hidden Power (physical) version.
-More move combos (like Rollout + Defense Curl) --->Outside of Triples/Doubles.
-Add team _____ to the Battle Subway.
-Add costumes (maybe not customizable per se) but allow us to dress as a Trainer or past trainer (with updated costume) during the main game/etc.
Can't really think of anymore at the moment.