Sure, I fully acknowledge that Unity (or Unreal) will let you produce a game you will be able to sell quicker and cheaper than other options. Those two haven't completely overtaken the industry for no reason. I just don't think this leads to better games. Unity isn't certainly isn't without disadvantages compared to IE or other bespoke engines.Not wanting to go into the merits of particular engines like unity or even the Infinite Engine, from the viewpoint of companies it is just that generic engines like Unity end up being useful for them. A company that was going to use infinite engine for a new project today would probably need to put any new workers on learning duty before they can start doing useful work. [...] Furthermore, you lack any resources that you might get from unity directly such as using it for mod support or getting assets made specifically for it.
I also would not recommend using IE specifically unless you really want to make I-Can't-Believe-It's-Not-BG. But IE and Unity are not the only options. While a custom competitive 3D engine that can do modern graphics will not be financially viable for anyone but the biggest studios, the same is not true for making your own IE-like. That should be something at least a medium-sized studio with competent programmers should be able to manage - after all, game studios back then did and making a 2D engine should only have gotten easier.
You will also need to implement those same rules with Unity.If you aren't using AD&D 2e rules, you will need to make changes to the source that will probably reflect into changes on how the other files are used as well, so even if then new hire is a BG modder, he would need to go through that.
You might disagree with their enhancements but Beamdog at least think they have been maintaining IE. Can't speak for their mobile versions but at least the Linux port is solid.Also, since no one is maintaining IE, you would need to support any system incompatibilities all by yourself.