I would restart anyway, and there are a few reasons.
1. It's incredibly easy to level up to 70 now (about 80% easier than before). 1-70 will take you about a week of casual playing and 1-3 days of heavy grinding. 120 is about as difficult as 70 was a year ago.
2. 68 base dex is just too high. I could understand continuing on with ~30 base dex at a very high level, but 68 at lvl 6x is just too high to be reasonable.
3. Your character won't go to waste! When you create a new character, it will get a skill from your other one (just don't delete your spearman). For every 10 levels you get, the other character on the account gets +1 attack, 1 avoid, and 1 accuracy. So, if you start a new character, you'll get +6 to all right off the bat.