Hi welcome to Epic - Short answer, IMO yes, you need a carver of some kind for Tahoe to complement your Prophets when it's been a while since the last storm. Longer answer: It would help if you talked a little about your size, style, where at Tahoe you like to ski, what other skis you've liked.
Second, try searches with keywords like "2010 skis" or "(brand of your choice)" and some of the threads will be reviews, ranging from carvers to fatties. Sierra Jim and Dawgcatching both post informative multi-ski reviews, and ski in the far west, so good feel for your type of snow. Third, nearly every company makes nice 70-something carvers these days, so the choice may not be critical. Brands differ more in feel than in quality, so pay attention to what feel makes you like the Prophet, apply that to carvers.
Fourth, go Google Real Skiers, their reviews are pretty solid, especially for someone who's not already focused in on a brand or model. For a nominal $ you can join and have access to more detail, numerical ratings. I also find the reviews from Ski Press World (try their Ski Finder, it's faster than leafing through old e-issues) and Ski Canada to be useful. Latter posts info about individual testers, which skis they liked. Less enthusiastic about Skiing/Ski. Good luck.