I wouldn't unreservedly recommend the unofficial patch. Even fairly early versions were well into the territory of highly debatable 'fixes', and the introduction of new bugs with version changes seems to be fairly normal, even if they're quickly addressed. Still, it's undeniably a praiseworthy effort, and they do list changes, so it's easy enough to decide whether you want them or not. I think 3dgamers hosts most or all of the old versions, too, so you have the option of getting an earlier one if you prefer. If you don't unofficial-patch, I would recommend at least activating the character backgrounds (a simple cfg edit - sorry, don't remember exactly how to do it) - the released version had them turned off because a couple cause crashes on selection, but they're a neat enough addition to be worth that irritation.
The plan of playing once without the patch probably makes a lot of sense. It's one of very few games I think rewards replaying (helps that it's fairly short) - there's no narrative branching to speak of, but the differences arising from clan and skill selection and humanity choices are appreciable. Seduction is never worth the trouble, though, unless you actually want to exaggerate the kind of irritating puerile-porny atmosphere that pervades a lot of the game.
About the combat-heavy endgame: you get positively showered with skill points towards the end, so it's not unmanageably difficult to develop respectable combat skills very late. Personally, though, I found half-decent sneaking (which, as noted, is fairly insanely effective even at moderate level) was the most important tool for making the slog through the last couple of missions bearable, especially the Tiresome Lair of Respawning Chinamen.
