It's a good idea.
At the moment I've released only one game. But when I launch my second one I'm thinking about updating my catapult game, so that at app launch it shows a big advice with "new game released!". If I have a user base of , lets say, 2000 players, I think it could be a great way to promote the new game.
And before showing the ad check if the user has allready intalled the game, you don't want to show it if user has allready downloaded it.
And (just thinking), maybe you can offer an "incentivized" install. Something like "download new game and earn 20000 coins!". You can check if user has installed it to give the reward.