Oh, I'm very aware of that. There's this very real phenomena with older League characters, especially those with niche fanbases and no current lore updates, where fans basically had to cobble together their own lores based on the brief biography, a Judgement if you were lucky, and maybe a minute's worth of lines. That sometimes results in a bit of a disconnect when Riot updates those champs (Leona/Viktor say hello), and I've always found that interesting.
I personally like to see Vlad as an addict. It's not that he wants to use hemomancy, he literally has to. It was actually confirmed in an old Red post, though I'm unsure if this is still canon, that Vlad doesn't heal from using blood, he heals off of the sheer thrill of it. Of course, that's probably just to explain "how does Vlad heal off Malphite/Blitzcrank", but it painted Vlad to me as someone who's obsessed with his powers, and needs to use them to survive. Being in the League, when that was canon, gave him a chance to do all the blood sucking and hemomancy he wanted without being arrested as a serial killer. They all come right back anyway.
And of course, nothing I said above is canon. I don't have much to work with to support those points, which is why I do agree with Blood Magicks on what I think their main point was, Vlad really could use some more lines or lore that better illustrate his personality and motivations. Hopefully we'll get that.