I for one would be all for this, whether getting to actually experience true vampire gameplay is included or not. I'll admit that I've been thinking that a great 'endgame' scenario of romancing Astarion and keeping his affinity Very High/Exceptional could include not only him becoming a true vampire (I do so hope we get the chance to confront and defeat Cazador, as challenging as that may be) but perhaps the dilemma/option of turning you as well. Would be interesting to see how he would handle this decision, what kind of sire he'd end up being given his past. And just maybe, if lurve develops and triumphs, becoming one of those "it never happens" scenarios after all.
Hard to say where the story will really go ofc, but one can dream.