The change to EK is a good one, and will make the base class much more powerful. Feats are a big choke point for hybrids, they basically never have enough.
One thing though that is really holding hybrids back is that you currently need to play them on easymode and ideally dump a whole lot of feats into your secondary stat as well. Fan introduced a nice secondary effect to bladesong-style way back when he changed the class: http://www.realmsoftrinity.com/Forum/viewtopic.php?f=69&t=2899&start=70
Bladesinger's blade song style now grants an AB bonus equals to the difference between the Int modifier and the Str/Dex modifer. This bonus is capped by half of the bladesinger level you have.
How about a feat that would give you the difference between either inteligence or charisma and dex/str. This is inherently balanced because you are missing out on damage dice from STR or AC from dex and have to spend a feat. Not to mention that bards already have the option with snowflake wardance and clerics have the option with intuitive attack/zen archery.
You can similarily cap it by a quarter of the BAB of the class, restrict it to high bab or a certain treshhold of class levels to prevent abuse, but there honestly isnt any combination that comes to mind that is inherently overpowered, as long as you require a level of sorc/wizard to take those feats.
A second Quality of life change would probably be removing the line of code that strips Tenser when you cast a spell. The idea was very cute in the beginning, but it is making playing a Gish very... un-fluid. If you did tenser as a on-off thing that prevents spellcasting, i'd much rather see it as some sort of mode like combat expertise.
Thanks for taking a look at hybrids though, seeing as how that is the only thing i play, i really apreciate it.