Now, you might say this is just how the game was made, it is not its responsibility to cater to any kind of build the players want. Well, to a point, I suppose, but the issue is that the game is really happy in letting you get ahead early on without focusing much in combat. Many of the early quests have easy workarounds for people who focused in other abilities; and with a tiny bit of sneaking, it is easy and even sometimes fun to avoid enemies. About half-way in, this design philosophy changes completely.
That's just how all badly managed RPGs turn out, plenty of branching and C&C at the start, the game letting you pursue a wide variety of builds and then towards the end the devs don't have the time and money to maintain that so they just throw enemies at you since that is the cheapest way to pad out the game at that point. Bloodlines still did the branching thing at the end, but it couldn't keep all builds equally valid. That renaissance Fallout clone, Lionheart, is a much more extreme example of this. The budget ran out completely in the middle of the project and so after a certain point the game turns into pure slaughter.
Consistency is the best thing here, if you can't offer a wide variety of playstyles for an entire RPG you should either scrap some of them or just cut the game down until you can. If Bloodlines had been more combat focused from the start it wouldn't have been so annoying when the change happens and the devs could have focused on polishing the combat rather than wasting their time on all that juicy good stuff at the start.
It's not even purely a money issue, I've played some Neverwinter Nights modules that did similar things, going for a combat grind towards the end. So I think there is some design issues involved too, that you have to write the game scenarios to fit with that gameplay variety too. Alpha Protocol did this with the bosses too, that suddenly weren't stealth-able, or in the Deus Ex reboot where the bosses also suddenly broke a stealth run for no good reason because there needed to be an epic fight scene all of a sudden. That couldn't have been due to budget reasons.
Arcanum is actually completely consistent from start to end, throwing some combat at you, but letting talky players survive those thanks to more followers and even letting you persuade the final boss. Minor playstyle alterations like taking up gambling or haggling is useful at points, but is never established as something that you will be able to depend on entirely and since you get XP from killing things that is explicitly a goal.