I guess in response to your "why would honda bring the TSX (Euro Accord) into its lineup?" comment I would ask "why would honda make the accord as big as the avalon?". The answer to both of these question is "they probably won't." The euro accord being sold under the honda name as their new smallish-midsize was just a very unlikely possibility i suggested given the rumor that the 08 accord would be so much bigger, which i doubt it will be but it is always possible especially given that we have very, very few details of the gen8's.
IMO, bumping up the 6mt's performance any more would close the gap too much between the already only very slightly better performing TL, aspec and s, and would impact acura sales negatively. The TL is a lot heavier and is not all that much more powerful.
I definately think the TSX needs a few powerplant options though. That 4banger kind of turned me off, even though it's a great one.