I beg to differ from what I've seen so far. I play my game with Harsher Settings and as such has a pay a load of caps to buy anything and don't get much back when I sell things. I had a caravan merchant repair my Ithaca Pump Shotgun (spelling) to 100% from 50% for 28 caps. If I had to do that myself I would need to be much higher level and possess the items to repair it as well. And that is worth 28 caps?
One could argue that the repair merchants may have both a workshop with a larger assortment of spare parts, making it cheaper for them to perform the actual repairs. As an example: With a decent repair and a workbench, you can make two repair parts from two scrap metal (total value: 10 caps + work). Yes, it may be a bit on the cheap side to set work at 28 caps, but it is enough to buy a meal at a vendor. But this is again a matter of balance. Tagging repair allows you to carry a lot more value into town, effectively increasing your income like, say, tagging the Barter skill. Furthermore, tagging Repair keeps your equipment in better condition, meaning that you use fewer bullets to kill enemies, and need to use fewer stimpaks as your armor absorbs more damage. If repairing yourself is cheaper and of higher quality than the repair vendors, tagging repair will also save you money, again reducing the value of Barter early on. This is a major consideration, because once you get a bit into the game (around level 7-10), you will be swimming in caps, and Barter stops to be that useful. And we haven't even touched the advantages of crafting.
I should point out that I don't disagree with your points: At 100 repair at a workbench, you should be able to repair your stuff cheaper than the best vendors, but it needs to be balanced with Barter. Would it be possible to reduce the effect of condition on the value of weapons and armor?
The same could be said concerning Medicine. Why doesn't a doctor at least request to be paid for the stimpack or Radaway he used plus a small bonus? If I had to heal myself of my cripped limb even with a high Medicine skill it would cost me considerable more than he could do it.
I agree on that one. Medicine is a bit to weak in the game, so increasing the price of going to the doctor would be a good idea. Could the price be made dependent on how hurt/irradiated/addicted the player is?