Combining kits simply cannot ever be made possible. First of all, every kit is designed to have its own strengths and weaknesses, and combining would allow the weaknesses to be covered. Also most kits can be grouped in either 'fast kits' and 'strong kits' in which i mean that the former allows greater mobility while the latter makes you harder to kill. A combination of 2 kits from both groups would be absolutely op.
I agree with paying other players but combining its too op. like transporter+scout+assassin so don't add the combining kits
Paying others with xp +1 Combining kit -1 Men you made a monster (Scout + Acrobat = no fall dmg Scout) or (Handyman + Assassin = gg rush and nexus repair)