Thanks everybody for the entertaining discussion in this thread, I learned something new about SegWit (WITNESS_SCALE_FACTOR). Thanks Lauda (and Sipa on IRC) for explaining.
Wouldn't segwit hard fork be better than soft fork?
2.) There will be less technical debt by implementing segwit as a hard fork. The software kludges implementing it as a soft fork also creates huge maintenance risks in the future (segwit keys are 'anyonecanspend').
You are wrong here. Exchanges pointed out the need for replay protection for even slightly contentious hardforks a while ago. Replay protection is quite difficult and would cause more technical debt than SWSF. This makes SWSF the currently superior solution.