Fc tis..very few Evo buyers will be cross-shopping the MS3. Punks who spend their entire Best Buy paycheck on their car each month aside, most of the buyers will be 30 somethings making decent money. They'll undoubtedly be cross shopping the Sti along with even more expensive rides from Infinity, BMW, Lexus, etc. This is why Mitsu did what it did... An by that I mean, make it heavier. By doing so it also made it a lot more refined... and at least capable of being considered with the likes of the aforementioned cars. (conversely, the previous gen was more boy racer... attracting kids who really couldn't afford the car but usually found a way to pay for them anyway.)
So while the MS3 is clearly the best bang for the buck... at least right now, the fact that it's a better deal than the Evo is completely irrelevant. The 2 cars are in different classes... and cater to different buyers. People like us (that is, people that understand cars) know awd is over-rated... the masses eat up all the PR garbage and are willing to pay the premium. Combine that with the "300 hp" badge of honor along with the cachet of owning an "evo" and those same people will be more than willing to pay the extra $10k over an MS3...
As far as any possible buyer's remorse goes... since this car (especially the MR which I'm skeptical you actually saw but I could be wrong) is A LOT more expensive than an MS3, you really shouldn't feel any remorse. As I said, for the price, the MS3 is hands down the best bang for the buck you can get.
But all that could change soon... Once the Raliart hits the street. On paper, it appears to offer much of what its big brother's got... for about $10k less... or, for about what the MS3 costs. Sure it'll have a few less ponies (something that can easily be fixed) but it'll have AWD... If I'm in the market for a $25k 4 door pocket rocket this summer, as much as I love the MS3, the Raliart might become the new king. Especially now that Subaru neutered the WRX