There's a handful of cards that can gain the activated abilities of other cards. Myr Welder, Experiment Kraj, etc. Any chance there'll be cards in the future that can gain static or triggered abilities in a similar way?

(Cards like Soulflayer that only get specific keyword abilities don't count. I'm looking for open-ended mix&match jank potential.)

The rules have a lot more issues with things gaining static and/or triggered abilities. Whenever I try, the Rules Manager says, “How about activated abilities?”

I'd like to express my bitter disappointment that I won't be able to play Hanweir, The Writhing Township in my EDH Experiment Kraj deck.

The team that decides that isn’t at Wizards. Yeah, I need to update my FAQ.

In response to your question of legends we'd like to see (my playgroup and I are crazy for legends, even ones that suck in EDH): Somehow, a legendary Sliver, A Legendary mutant (but personable/humanoid, not like Kraj), A legendary Nightmare (or just bring back Nightmares in general!!), and a legendary Vedalken would be nice since we've yet to see a single one of those, I believe. ^.^

Legendary Slivers: Sliver Legion Sliver Queen Legendary Mutant Experiment Kraj Legendary Sliver & Mutant Sliver Overlord Legendary Vedalken Nin, the Pain Artist I’ll see what we can do about a legendary nightmare. EDIT: Okay, Kraj is quite a bit like Kraj.

Experiment Kraj was really "the final experiment" (from krajj, "the final number"). Does Experiment One mean that the Simic are starting over?

That’s a cool way to look at it.