you know, you don't have to change the surrender mechanic's appearance. Just make it different from a lose mechanic. ie, if you lose, keep all points, but if you surrender, keep only 1/2 or 1/4 or 1/8 or something (refunded to balance with tree at 0). Heck, that could even be a skill upgrade (to go from 1/8 to 1/4 or 1/4 to 1/2).
Also, the surrender mechanic is only such a big issue because of the collect war-points on number of levels regressed. On that note, soft landing seems to actively work against that skill.
Neither seems to stop the farming of levels 1-3 though with the skills of:
get 2/3 upgrades per level, 1 per down-level and big bertha - Auto-win without units until level 4, surrender and collect regression points, rinse and repeat.