*Snip*
I've heard that soul history is the only decider on matchup, but honestly I have no idea. Well, whatever the matchup system is it wouldn't be strange to see people in the 90-100ish sl range matched with you, so I'm just going to assume the red was around there.
Now, ever since I've been a part of the Souls pvp community (since the early days of DaS1) Hp has been considered one of the most important stats for a pvp build, so it wouldn't be strange to see someone around 40 vigor by your level, maybe even all the way up to 50. According to wikidot, you get 30 hp for every level in vigor from 0-20 and 20 hp for every level from 20-50, so that is 1200 hp just from vigor. Additionally, you get 2 hp whenever you put a point in any stat (whenever you level up) so we can assume this guy is getting around 200 hp just from his SL. Now frankly, I have no idea what base hp is, but looking at my character's stats it seems to be around 600. So 3k sounds like a bit much to me, but it wouldn't be strange to see someone in the low 2k range at this point. So maybe the covenant does affect that or maybe you're just exaggerating, If he was wearing heavy armor it would make his 2k hp count for a lot more.
As for the two shot part, it doesn't sound very strange to me. Getting two shot is a pretty common occurrence on my dex build with ~17 vigor and 1200 hps. He's rocking light armor cause I wanna be mobile so I'm probably a bit lighter armored than you (full bandits set cept Varangian helm cause it looks cooler), but you sound like you have even less hp and I can get two shot by things like enchanted katanas. So if he was using an enchanted weapon, especially a heavy enchanted weapon, I could definitely see you getting two shot.
Also, does the lag seem worse than ds1 for anyone else? Everyone I've fought seems to get ridiculous phantom range and I seem to get lagstabbed more often. One guy even managed to get a backstab when on my screen he was standing in front of me. It's really annoying when a fight is going my way and then I get backstabbed out of nowhere.
Personally I've found the lag a lot better. I played tons of PvP (probably somewhere in the area of 200 hours just on PvP) in DaS1, and I used to get lagstabbed about every other match. Never quite got a hand of either landing back-stabs or avoiding them, kinda why I stopped fighting in Kiln.
Now I definitely get some lag still in DaS2, I've been lagstabbed once or twice and it's an annoyingly common occurrence for a hit to land on me when I'm 15 feet away cause I rolled, but I'm no longer getting lagstabbed every other match so it's all cool.