too low profitability means that we need a new coins ?

There are no new profitable altcoins right now. LTC is becoming more and more worth mining now.
I cant agree with you. Just take a look on coinwarz.com - there is a 10 altcoins with profitability over 100% than LTC

For example - GDC have 256.93 %
http://www.coinwarz.com/miningprofitability/litecoin