1. ITEM SETS
If there is a way to set these up with the new client I can't find it. I love being able to create custom item sets for my favorite champions and having to revert to the old client to do so is a pain.
2. STEAM LINK
I doubt many will care about this one but the new client does not work with Steam Link. I have to hot foot it back to the pc until the champ select screen then go back to the lounge room. I know this won't effect a lot of people much but it's problematic to me.
3. WAIT DISPLAY TIMES
In ranked with the old client it would tell you if the roll you have selected would result in a longer or shorter wait time. The new one does not and I found that a handy bit of information.
In conclusion I love the new client but if I want to make or edit an Item set or play with steam link I need to revert to the old client. Would really like to see these fixed/implemented before the final release.