if any coin gets added, it should be one that genuinely offers something unique to the community... not just some other altcoin that claims to do X or Y differently, but is functionally no different than any other coin.
NXT would definitely fit that bill, but perhaps NXT's development needs a bit more maturity first. BTC-e wouldn't be able to just drop it in like they could with most other alt-coins... they'd have to write a new api to communicate with it... but having NTX/BTC, NTX/LTC, NTX/(fiat) pairs available to trade, would definitely add some value to BTC-e...
=squeak=