Langi has been inconsistent, but he has also shown improvement. And there is every reason to think we will see a good amount of improvement between this year and next, as I said above this is his first year playing ILB, he will improve.
Warner is not too small, he is actually a little bigger than KVN was at this point in his career. Please, explain why you think his size is an issue?
Tautu actually has been consistent, you are just wrong on that one.
If he is back there is also a lot of reason to think Takitaki will improve, he has very good physical skills and good instincts. And if he puts in the work, and it does appear he has started to change, he will improve, at the least he will be a very good pass rusher. Takitaki was improving in different areas before he got kicked off the team.