That's too bad. I haven't looked, was hoping the classes would be freshened up.
Most of them are being, although they are still basically the same classes. (Artificer isn't). Wizards and paladins get the least because they are already at the top. Monks get a huge tune-up. And there are a few targeted nerfs (such as to low level moon druids).
Much of what 5.5e changes (as of the most recent playtest doc) is stuff I don't really feel fixes any of the issues, it just shuffles them around.
A few of the changes are really quite good, but rarely go far enough (e.g. the Playtest 7 Warlock gets...1/day half their spell slots back. Woop-de-friggin-do. But it also makes pacts into invocations, which is great.)
This is a good illustration of where the changes actually are. If you're playing the old hotness of an Eldritch Blast spamming Fiendlock who has spent their invocations boosting Eldritch Blast that's all you get. Because you were already good.
If on the other hand you wanted to play a Bladelock you now get to attack with Cha rather than Str or Dex - and you can take medium armour and a shield as a first level feat. And as a fiendlock you don't just have to take someone to 0hp, you also get the temp HP if they drop within 10' of you through someone else's actions. You can front line bully weaker foes.
Meanwhile if you want to use invocations to side-buff your being a bladelock the Jump spell was massively upgraded (so that's now a good invocation), and the two Invisibility invocations were merged at fifth level (so you can turn invisible in dim light at will); all the higher level ones came down to a level where they are now good. You're now an oddly moving nightmare.
And if you want to go for a different pact, for example the Archfey, that got a massive tune-up; it's now based round Misty Step (and you get free Misty Steps that have effects when you use them). So you're a weapon wielding, oddly moving, teleporting nightmare. When before you'd have been trying to hit with dex, wearing light armour, and not bothering with Jump. Is this combo stronger than the old Fiend with multiply boosted Eldritch Blasts? I don't know - but it's now a conversation worth having and hella fun.
Overall, I think it will be better; I just struggle to summon enthusiasm for 5.5e because of how dim my view of 5.0 is.
To me the major problems with 5e are on the DM side not the players side. And we haven't seen that.