Plane Sailing
Astral Admin - Mwahahaha!
I'm not sure what you mean here. What kind of modifications do you find difficult in this version that were easier in past versions? I haven't found that to be the case so far, but I can't really offer a good counter-argument or suggestions on how to make modifications easier unless I understand what you are finding difficult to modify.
How so, if you don't mind me asking.
My group's found that it's been extremely easy to make 4e work for our gaming style/take on fantasy, which is idiosyncratic, to say the least, and not at all like the style implied by any of the 4e published modules.
Or any published modules, for that matter.
As KC has mentioned, creating of new classes stands out.
However, for me the main thing is that for all previous editions of D&D I've dramatically houseruled things to give certain unique campaign flavours - sometimes in terms of magic systems, sometimes in terms of additional combat options. Plus I'm a very simulationist sort of guy. Take what was done with Conan OGL, Black Company, Wheel of Time and Midnight, for instance. I typically do that kind of stuff myself.
3e was harder to houserule effectively because of the interlocking relationships between all kinds of stuff. 4e makes that interlocking relationships thing go even further - plus it takes a big step away from simulationist rules.
In many ways my favourite RPG systems are like well designed applications - high cohesion and low coupling. 4e seems to me to have taken the coupling of things to a new high.
So, while in 4e it is possible to add a new power here or there (but even that is difficult as the strategy for creation of powers is particularly opaque - I don't know whether WotC has a plan, or whether they just eyeball everything), and it is possible to go wild with 'reflavouring' stuff, adding new subsystems or changing existing subsystems is much harder for me.
Please note - I'm not trying to tell anyone else how to do things, and it isn't because I'm stumped and need help in working out how to do specific things with 4e. I'm just running a pretty vanilla 4e game at the moment, after all - although that is because it would be too much work for me to change stuff to make it work in my old campaign setting (for instance).
Cheers