So are there any other changes to it? Do they still get spell DR and other nifty abilities, the ability to use magic devices, etc?
Also, 24 Invocations + Eldritch Glaives seems like a bit much. Do they still get the ability to replace invocations?
These are changes. Things that aren't noted are unchanged.
24 isn't much, IMO. They are weak due to lack of options. More invocations give them more to look forward to each level, and they are not s strong as spells anyway.
All gaming systems should be terribly flawed and exploitable if you want everyone to be happy with them. This allows for a wide variety of power levels for games for different levels of players.