Yes, I'll do it once each match and as the tournament progresses everyone will start doing it, creating 2 games in each match that are uninteresting.
I do like the idea of a twist, but make it a different one. Some ideas:
-A few days before the match each player chooses a pre-constructed Kingdom (from the expansions, or one from the dominionstrategy tournament). Both players can then study both Kingdoms and try to find the optimal strategy for that specific Kingdom which is a slightly different skill than deciding a strategy on the spot.
-add one multi-player game to each match (finding volunteers might not be easy or practical). Whoever finishes higher in that game is the winner (the volunteer might actually win that game)
-add one game where the goal isn't to win the game (VP), but to reach one of the Councilroom goals (like "piledriver" or "Oscar the grouch"). Whoever gets it, or gets it first, wins that game.