Everything you wrote below this though proves my point 100%. This is just a way you feel. Its not objective. Its not based on reason or thought. It has its roots in the meat of the animal mind and the associated biases and feelings that make up your operating system and your formative experiences. Its more a reaction formation than a considered opinion.
Somethat right, and somewhat condecending indiocism. Of course my liking of BG1&2 is subjective. And of course, when being offered BG3 I expect for it to tickle me in somewhat similar way. Baldur's Gate3 is in many many many many many aspects objectively different then BG1&2. There are bunch of individual changes people are pointing to ever since BG3 was revealed, and if you still don't grasp the different then pick up BG1&2 and give it ago. If you hurry it's about £5 for both on GOG at the moment. You might not like it, but at least will give you an idea of how they are different.
If you give me tiramisu there are things I expect from it. If turns out your tiramisiu is a brownie, because it is what you make, and you just called with tiramisiu because marketing? And sure both have cocoa, and it might be a very nice brownie, and I generally don't mind brownie, and if you never had or liked tiramisu, it might not bother you, but it somewhat bothers me.
Gaming should stop sticking to IPs. Sequels are only of value, if there is room to improve. You did one game, you want to do it again, but better - that's a sequel. If you want to do "spiritual successor" or use one or two ideas and do you own thing, just create your own IP. All you do is piss people off, who liked it as it was, and want more of the same, updated with newer technology.
EDIT: And returning to the subject. 4 vs 6 party is a different dynamic. And in a wide contect games that focus on innerparty interactions and synergy have 5-6 men parties, while RPGs that don't tend to stick to 3-4. It doesn't bother me a whole lot, but combined with unification of classes and homebrew rules made by Larian, and overal limitation of spells via concentration the difference is quite stark. Different goals, different interactions, different gameplay.