I've been on Linux for many years now, so here is at least one vote for Linux support, heh. On the plus side, the vast majority of Windows based VNs will run just fine through Wine. The only use I see in HTML5 support would be for entries to game jams and showing off prototypes. I otherwise tend to hate playing games through a browser, with all the extra overhead and limitations that imposes, not to mention all the special exceptions your end-users have to deal with to avoid the save data getting hosed every time they shut down the browser if they're using a variety of privacy protection extensions in their browser.
I will however say that not all engines are created equally. Ren'Py stuff runs like a dream, assuming the game isn't made by someone entirely inept at basic coding. It focuses on VNs, supports most of the major platforms out of the box, and is pretty easy to pick up the basics of and since it's built on top of PyGame, you can always drop down into that to introduce more advanced mechanics into your game.
Unity is a steaming pile - performance wise - in most cases for me. Often games made with it will even take my whole system down with them; I tend to avoid games with the Unity flag because of this.
RPGM is hit or miss; I'm guessing some of it could come down to how a dev makes use of it and what sort of dodgy addons they may be using. Sometimes games run just fine and other times I see them doing terrible things - like pegging a CPU core at 100% non-stop the entire time the game is running, often sticking to the same core for several minutes straight without even attempting to do any sort of load balancing. That kinda shit is unforgivable.
TyranoBuilder games tend to be buggy messes and they often have a lot of weird limitations. Like very few save slots and if you don't make a point to create a unique save context for your game, it will just use the default one shared by all the other games made with it by lazy devs who also ignored this issue. This means those limited save slots are now being shared by multiple games... blah.
UE4 is overkill for most games your typical indie eroge devs are likely to come up with. It's a huge resource hog and is a pain in the ass to extend as the source code is such a mess. You really need a team consisting of UE veterans to make the most of this engine and even then, it will likely burden your otherwise rather basic game with absurd system requirements.
Godot is an underappreciated engine still atm. I think it might have the most promise out of all the various options available to indie devs. It's open-source under a very liberal MIT-based license. Meaning it is completely free to use and modify, with no subscription fees or royalty payments. It has one of the cleanest source codes I've ever seen in a game engine; I usually hate reading through C++ code, but Godot's is very tolerable. It is very light weight on system resources, opens up pretty quickly, rarely crashes as far as my testing has gone so far and exports to a fairly wide variety of platforms, including several consoles (if you have a development deal with one or more of the console companies in questions.) It comes with a really nice Python-like purpose built language built in, called GDScript which is really easy to learn and quite powerful. For those who prefer C#, Python, and a few other language options, there are modules to support working with those instead; you could also always drop down into C++ if need be for more advanced needs. The editor is really nice; the code editor in particular has some rather advanced features - if you stick to GDScript - that make it a pleasure to work with. It has rock solid support for 2D games and recently got a big overhaul for the 3D side of things, including support for modern PBR materials. Though I'd probably hold out for the next release before looking too closely at the 3D side of things, as there are plans for adding in a terrain editor and they will be adding back in their node based material editor that was temporarily removed for this release while they reworked it for the new updated backend.
