The only problem is that PMD has no stat cap on vitamins, so there's nothing preventing you from gathering hundreds of them to get everyone's stats to 999.
Well, technically HP can be raised to 999, but the natural stat cap is 255, and they can be raised over that by the various stat boosting items but...same difference. :P It would be interesting to see PMD made competitive. However, if anything, turn order will have to be changed to accommodate multiple players. After that is fixed, I'd be interested to see what prevalent strategies crop up (Palkia with Agility support? Rain Dance, Swift Swim party abuse?), and thus what stat/item limitations and tiers are needed to establish to keep balance.
Anyway. Most memorable moment in the game...in PMD Red, it was finally, after DAYS of trying, recruiting Jirachi. I wanted to have it grant my wish instead, but after the pain of going through that dungeon, I just wanted it to be over. Some other things I miss--Friend Areas, the way gummis worked for dual-types, and the Pokemon looking like they're actually waking up from sleep instead of...walking in place for some reason. Overall I like the mechanics of Time/Darkness/Sky better, though.
Personally I love playing Skitty--it fits me and actually isn't bad if you play to its strengths--but as far as optimization goes, I found Charmander and Pikachu to be the best starters, the former in the original PMD and the latter in Time/Darkness/Sky. Charmander is awesome for obvious reasons already stated, but even though it's still pretty solid and Heat Wave's worth the wait, the transition wasn't so kind when starter evolution was postponed to (IMO) ridiculous lengths. Thus, Pikachu--say hello to Discharge and Agility, and excellent IQ skills. It gets good stuff late, but at least it can potentially get it before clearing the game. Shinx also gets Discharge but I prefer Pikachu's IQ set; either one works.
Because I get anxious if I don't think I'm playing as "optimally" as I can, I only recruit legendaries and Pokemon I want to solo with post-game. My favorite is Masquerain, though Flygon is also very good. I know, I'm boring. I just find the AI rather annoying to deal with. :P Below is a block of text offering the builds I used if you're curious.
I find D-group Pokemon optimal as solo-explorers. Trap Seer lets me equip a Tight Belt, removing any necessity for food, then Concentrator (best IQ ability IMO) reduces the need for Max Elixirs alongside PP Saver by making every hit count, and making room-sweeping moves more effective. Quick Striker gives an unlimited neutral-type move that is as good as a standard attack, and Hit-and-Runner protects from critical hits. I am pretty biased toward the Trap Seer skill in general, but anything else is also fine to play solo as long as it has some method of crowd control, and a Trap Scarf helps. :)
Flygon's build - Silver Wind, Flamethrower, Dragon Claw, Earth Power
Flygon is cool. Its movement type lets it sail over all terrain, though it can't go through walls. It learns two room-cleaners, though one of them takes...a while to get without Golden Seed assistance. Ahem. Worth it though; if you've ever cursed at Pokemon using Earth Power on you, now you get to laugh at them and use it right back due to Levitate. Its typing in general is excellent. I included Flamethrower to deal with Shedinja and distant foes (when I want to conserve other PP), and Dragon Claw was coverage/filler/deals with Salamence, pesky thing.
Masquerain's build - Ominous Wind, Blizzard, Silver Wind, Agility
Probably the candidate that best fills all my ideals. Can move pretty much anywhere bar walls. Though its typing isn't as good as Flygon's, it's got THREE room cleaners, but if that's overkill it's easy to replace one of them with, say, Bubble or Bug Buzz or something (wouldn't replace Ominous Wind, though: Shedinja). Best thing is, all three of those can potentially be obtained immediately after Surskit evolves, and Surskit can be recruited very early. Agility can also be swapped for something (Surskit gets it at level 31 so if you don't want to wait...), but I find it useful more often than not, especially against Kecleon swarms. Quick Striker gives infinite neutral coverage and way to deal with just solo opponents, more useful here than with Flygon.
That's all. @u@ Wonder what optimal builds other people have come up with?
Anyway, love these games. Can't wait for a BW version...hopefully.