I've juggled the Skill Lists, looked at related Skills and Defaults, etc a fair bit, and I've considered some similar things, but nothing so drastic.
A GM should be reviewing the Skill List and defining the allowed skills for any particular campaign, along with any specific skill amendments. The DF Skill List has 149 skills (down from the full 270+, and pretty close to your 120).
Shifting closely related skills with good defaults to a single Primary Skill and optional Techniques or Specialisations seems like a reasonable idea.
Several skills could be changed to Professional or Hobby quite easily, but I'd agree with Ze'Manel Cunha about some of your choices between Professional and Hobby. Then again, Professional and Hobby are more 'labels' and the real distinction is Easy vs. Average difficulty.
Combining all of the Influence Skills into a single Persuade skill seems like a bad idea to me. How are you going to deal with the distinct special effects of the different influence skills, in particular the fact that use of the Diplomacy skill mean no worse than Neutral reaction?
I suspect you might also need to give some specific consideration to Talents and the effect your changes will have on their cost/benefit. Some of your 'Super Skills' are pretty close to Talents, and some Talents are only going to have 1 or 2 skills now.
You could simply drop Jumping and Lifting (and possibly others) and simply use the standard Attribute based rules - Jumping is based on Move and/or DX and Lifting rolls against ST.
Some specifics:
- Urban Survival as a Survival Specialisation seems reasonable, but the defaults are entirely different (none for Urban!)
- Esoteric Medicine is not just low-TL Physician, Chinese Medecine (among many others) coexists alongside Physician in our TL - perhaps it should be a Specialisation of Physician, with little or no defaults.
- Economics might be better as a 'Business' skill alongside Finance and Accounting, rather than a 'Social Sciences' skill.
Fast-Draw off Weapon Skill seems like a good idea, but what would Kromm's
Fast-Draw (Rose) base off?
I think you also need to be careful not to cut some Niches down too much, Thief might have been reduced a little too much by your choices (I haven't checked, so it might be just fine). And Face Man from Action will certainly suffer from the loss of distinction on the Influence skills.
I'd also agree that you need to be careful rolling Physical (DX, HT) and Mental (IQ, Per, Will) skills together, but one or two shouldn't be any real problem.
I think anything like this has 2 important considerations:
1) Campaign Specifics - different campaigns may have different requirements, and rolling some skills together for one campaign might be fine, but would hurt another campaign considerably.
2) GM Style - If as a GM your games have less social interaction where the Influence skills make a difference, then by all means roll them together. If you have less of the gritty breaking and entering, pickpocket, crime action, then the Thief skills might not need to be as distinct.