For PvP, I don't think strength is very important but I'm not entirely sure.
For bashing, blademaster isn't as tanky as most classes (outside of Mir), so you'll probably want some con if you don't have defensive artefacts as Atalkez said. I wouldn't go full con, but probably 14/14 or 13/15 str/con. The best races for blademaster bashing are the races with 13 in str or con and 12 in the other (dwarf, horkval, troll, xoran), the 12/12 races are almost as good (human and rajamala), then some have useful non-stat bonuses (like mhun's faster movement and atavian's flight), but any race will be fine.
As told by @Zulah if you have the artefacts a band is more important than strength is. As for stats, con to actually stay alive and ensure your prep is performed then your attacks. I personally went with a race that was going to have decent con and strength and a stat pack. So yes look into a mixture that can assist you in staying alive but also looking into a band (if you can afford one). As Sena pointed above any race ultimately will be fine now we have different statpacks. I'd probably encourage you to look at the different stat packs offered and what can balance for what you're looking for. Hope this helps! I thoroughly enjoy blademaster.
Answers
Pretty much all races have the same stats within a point depending on which one you pick. I don't have exact numbers so @Sena will have to weigh in.
Penwize has cowardly forfeited the challenge to mortal combat issued by Atalkez.
For bashing, blademaster isn't as tanky as most classes (outside of Mir), so you'll probably want some con if you don't have defensive artefacts as Atalkez said. I wouldn't go full con, but probably 14/14 or 13/15 str/con. The best races for blademaster bashing are the races with 13 in str or con and 12 in the other (dwarf, horkval, troll, xoran), the 12/12 races are almost as good (human and rajamala), then some have useful non-stat bonuses (like mhun's faster movement and atavian's flight), but any race will be fine.