You don't need to bltiz agility. Shields are actually worse than they are in the other games at low levels, because stat requirements are higher for relatively low % block and stability, and it is harder to stack Stamina due to the vastly lower boost per point put in Endurance, and the generally worse poise (at SL1). All of the defensive abilities are nerfed at the SL1 compared to what they were in Dark Souls 1, not just i-Frames. If you want to the best roll invincibility, it is going to require a stat investment. If you want good roll distance, it requires a stat investment. If you want really good shielding, it will require a stat investment. If you want to take hits without staggering or taking much damage, it is going to require good armor that will require a greater equipment load, which requires a stat investment.
And I'd rather be dodging at low levels in Dark Souls 2 than I would be trying to tank things with a shield, personally. Just don't do the Pursuer as your 2nd boss. The game isn't linear, and there's, like, 8 or 9 bosses that could be "2nd". Pursuer is just the one where dodging is the best strategy but is hard to dodge effectively.
I played through the game three times, and at no point did I ever feel like the only way to progress was to have good i-frames on the roll. Hell, for most of the game, I found having a good roll distance from the improved weight mechanics to more fundamental to dodging effectively. People will sit down and analyze gifs of guys with wide sword archs (Pursuer or Old Knights) and act like that is the entire game, but it isn't.