My build for dual blade

The points you are putting into STR are just about the minimum for heavy armor. This is a usual amount of STR for a blademaster (although some builds go for light armor only). The place you are putting all your VIT points is into DEX since you only have to have 3 DEX every 2 levels for any sword's requirements and your build has 5. That will give you some evasion advantage (against physical attacks ONLY), a better chance to hit, and slowly a higher critical chance. Since magical attacks alwas hit, though, you will be a bit vulnerable to these. Most people put some points into VIT (with real debate about how many is optimal) as a bit of a buffer against magical attacks. At level 11 magical attacks from mobs are rare, but they get a lot more common starting after about level 20. This is not to say your build will not work if you develop other ways to cope with the magic attacks, but you want to be anticipating that development now.

1 VIT, 2 STR, 2 DEX is a build that will eventually limit you to light armor. It is also sacrificing some damage when you hit for some greater chances to hit (or to crit), some greater evasion, and some extra HP. Nobody can tell you if this is a good tradeoff, though. It is up to you to decide if this is the character you want to build and play. One warning about that tradeoff, though, is that if you use a lot of skills in your attacks, their "casting" time will pretty much determine the pace of your attack. I think blademasters who build 1/2/2 tend to be light armor wearing fist users who tend to not use skills and just beat up mobs really fast. Fist because the weapons have particularly high attack speeds (something like 2 attacks per second?) which complements that play style. It can work and I expect it can work following the sword path too if you are creative.