I think eltoo-based channels have problems related to not having a penalty associated with cheating, this has been brough up in previous editions of the newsletter: https://bitcoinops.org/en/newsletters/2020/08/12/#discussion-about-eltoo-and-sighash-anyprevout

There are also concerns regarding transaction pinning attacks: https://bitcoinops.org/en/newsletters/2018/12/28/#april