Sad thing is that probably nothing he learns will go on into Wasteland 2, since all the design documents are already written...
Well, since Arcanum is basically Fallout in a steampunk setting with crappier combat and some neat ideas about magic/tech where half of them work good and half of them not so good...
...I'd say he's got nothing new to learn except from the fact that Arcanum is a game with extremely high ups and very low downs, and depending on how you approach it and how lenient you are with its shortcomings you might find it a flawed masterpiece, or downright unplayable.
I am one of those that think of it as a flawed masterpiece, but I almost stopped playing it at least three times when I first tried the game. The first one one was at the starting area which is one of the worst areas of the game in all aspects, the second was when I was sick of the combat and went back and re-rolled an agile magician, and the third was when some quest items simply disappeared from my inventory due to Arcanum being a buggy mess. So I understand perfectly all those people that couldn't bring themselves to keep playing the game.
Now that I think of it, MCA *could* learn something from Arcanum, and that is why people actually care for Obsidian's games so far. Most of them are flawed, buggy and unbalanced but they have moments of brilliance that elevate them from the sum of their parts.
BTW, (I speak from experience here) LPs are a double-edged sword. They can give you extra incentive to play the game, experiment with options, forgive shortcomings and find it more enjoyable in certain cases, but they can also wear you down FAST. I would
never try my hand at LPing such a massive game as Arcanum.