Ok so IF it is true that the Pact of the Blade warlock is being reworked similarly to how the new player's handbook will be next year then it sounds like some of what Larian is doing may be aligning BG3 with the next generation of D&D which is what is arriving next year. Great, right? No, nonononononono, not at all...what I have managed to find out about the next generation of D&D can be summarized in one sentence: Wizards of the Coast are going burn D&D to the ground. Hold on to your 5e books like they are precious artifacts because when they go out of print D&D will be over.
Yeah, people said that when 5E first came out too... and 4th... and 3rd... it was true for 4th ed honestly but I mean many people still liked 3.5 the best. It'll be okay. Your GM can homebrew whatever they want or use whatever edition they want. Or you know, you can just switch over to Pathfinder like I did. At least Pathfinder's gish classes get support and can be interesting sometimes, and many are basically multiclasses designed to actually synergize naturally without needing to multiclass.
