Their bench is weak for sure, but luckily for them it's filled with young players, rather than aging/totally useless ones. Much easier to sell a prospect, than a total waste of space. They got 15,000,000!!! for Ibe!!!! Crazy! Their big problem is no alternative for Mane. They are so slow without him.
Also they will be in Europe next season, and I think Klopp already admitted earlier this season that he left the squad a bit thin, so he will be looking to improve starting eleven and also bulk the squad. They seem to have signed Robertson from Hull, which would be a really good signing for them, especially for just 8,000,000.
I think Arsenal and Man U are the vulnerable teams next season. Man U have no plan, they just sign players and throw them together (also Jose's infamous second season syndrome). If they do not win Europa and don't come fourth...could collapse really quick. Arsenal are obviously in a crazy situation.