If you can find a good project with a great team, great tokenomics and release schedule, then go for it. However, in 2017-18 projects easily collected 20+ million dollars, but now they cannot even fill 5m hardcap. So do not expect good returns now. But as market recovers, ICOs will be back and we'll start making 3x-5x returns in short term.
Also, I wouldn't wait in altcoins because BTC is dominating all of them. But If you're willing to wait a long time (till 2021), you can buy and hodl of course.