Agree or disagree? I think people who sold their litecoin year ago already regretting.
Most alts will die so most likely not. Unless you are unlucky and sell one of the few that might make it and even outperform the btc price increase.
Right now it is probably smart to sell useless coins and pick coins that might have some advantage over btc. Personally I have sold all unorginal coins like feathercoins, megacoins etc. Coins that don't offer any advantages over btc. And bought peercoin for long term holding (proof of stake, erergy efficent) and anoncoin because of their progress on zerocoin implentation and anonymity features in general.