So I just finished the game with a Rogue Spellcaster. It was more or less exactly what I was looking for, Didn't know deathblows worked with scrolls - that was really cool. By the end of the game I think I could've been more practical with a vancian spellcaster. But I certainly don't think any of them could've matched the melee capability. Would recommend.
I also found myself doing more melee than spellcasting in most critical moments, but that's just probably my method of ''time'' value in battles. But what's the point of having a spellsword if you're not gonna melee ? Equipment with damaging spellbindings was my bread and butter for a while but I found myself eventually just opting out for equipment that makes me better in melee and relying on just scrolls for spells. It wasn't too bad this way, as I didn't run short of scrolls at any moments, except when I tried spamming them all in a few boss battles. Though I did play with a party, so I'm not sure how the scroll management would've been if I were solo. So to sum it all up, It is very powerful indeed, especially if you can get off a deathblow maelstorm like Boeroer mentioned but I felt like I wasn't efficient enough towards the middle-ish of white march 2 and started to be more of a regular melee rogue.