I first got the 4th ed starter set when I was about 10 years old, although I'm not sure how old I was when it came out.
I remember several things about said edition which I feel could be fun.
1. More equipment options for units. Orcs used to be able to equip; halberds, great weapons, bows, spears, flails, morning stars, shield. (well perhaps not all of these, forgive my memory, but they had more options.
2. Cavalry should be more useful, step up and striking in I order have hurt them. Orc boy boyz especially, weak cavalry save and low I. Now DE Coldone Knights.....they are much better now, or were I suppose.
3. A balance between charging, step up, initiate, steadfast, and disruption which also takes armywide rules into account.
-Step up should remain in some form; remember ASF blackguard from 7th? Welcome to all elves now.
-Steadfast should remain in some form; Did your 40 orc horde flee from 5 chaos knights/dark riders/ a hydra?
-Charging models being able to attack before they die; Nice movement phase with your orc boar boy big un's/IC knights!!! Too bad you charged Khorne warriors with halbards/executioners/white lions/Stormvermin/anything with a higher initiative, now they hit you first, sure hope you brought 10+ cav models so you get a full rank of attacks!
I think this is a fantastic thread for generating ideas.
I think these ideas all need to be weighed together and balanced. I really look forward to a players mod of WHFB, those working on one, stick with it!