A menu editor would be nice, IMHO, not sure about a css editor, as it is not obvious to me how it should behave. We might look into such rather for the 3.0 line, though it is not impossible to try to see about it for 2.x.
However, I don't believe SMF core will ever have too many features. That's against its "simplicity" as principle, as it currently is, and as people like it to be.
There's another possibility however: if SMF core would be designed more extensible, more easily extensible, by other mechanisms as well, not only direct code modifications (mods), then it wouldn't be a problem that a feature is not exactly in core. As long as adding it is as easy as (for example) dropping the file implementing it into the right folder in SMF.
Like we do - or try to - with the subscriptions mechanism currently. Not sure if many people know
but the subscriptions in SMF are designed like a mini-plugin system of sorts: if one writes a file for another payment gateway, and follows the format expected by SMF (and not exactly documented ... eh, okay, not documented at all - this will be solved *cough*), and drops it in SMF's main folder, then SMF will read it and integrate perfectly the new gateway in its subscription system: you will simply have it available alongside PayPal. With only a file provided, and no core modifications at all.
Why should the non-existence in core SMF of other payment gateways be then a big problem, if the format for implementing others would be documented, and if for the rest it is this
simple to add another? (okay maybe writing this file is not easy, but once written it is not a problem if it is not in core, IMHO)
Just my 2 cents anyway.