The idea of making it more like SWSE is very good, that's a far better evolution of the d20 ruleset than 4e ever was. Personally, my wishes for a d20 Modern 2.0 would be something like. . .
1. Wound/Vitality or the SWSE condition track (with bonus HP at 1st level). The lowered MDT to being equivalent to a CON score really didn't do it as much as it was supposed to with regards to making PCs more fragile.
2. Increased use of talent trees, ala SWSE. A lot of AdC's, and even PrC's in d20 Modern could be folded into a single talent tree.
3. Elimination of the "D&D in the modern day" assumptions in most of the settings presented (Shadow Stalkers, Urban Arcana). I hated the d20 Modern core rules had reprints of D&D monsters for modern adventuring, like bugbears and illithids, but you had to buy a supplement to get more modern monsters like Grey Aliens, Yeti, Chupacabra ect. Monsters that were both modern and classic fantasy had the same old D&D stats, like Vampires and Zombies. d20 Modern Zombies couldn't be used, with RAW, for a survival horror zombie scenario because they didn't create spawn or infect targets ect., and vampires had the full Dracula-type suite of weaknesses and powers, instead of the vampires depicted in most other modern supernatural settings. Urban Arcana had lots of good classes that had superfluous magic thrown in which made them awkward in no-magic games (Arcane Arranger, Speed Demon come to mind)
4. Elimination of vancian magic. It's a sacred cow in D&D, but that's D&D and this is a modern-day game. More low-key magic, not running down main street throwing fireballs and lightning bolts.
5. Adding the level-based damage bonus from SWSE. Add half your heroic/PC-class level to the damage on all successful attacks.
6. Revision of the wealth system. It was poorly understood and often horribly misapplied by players. Nice in theory, but another system may be better in practice.
7. Elimination of the odd nonlethal damage system, that was often ignored anyway and made it virtually impossible to knock anybody out in unarmed combat through subdual.