That argument, in my opinion, is false. There are a ton of crpgs that offer a nice challenge for every combat while min-maxing. There are a ton of crpgs that offer variety of attack choices for physical damage characters (ranged and melee). The IE games offer none of this. The designed the game to have 90% filler combat but failed to make combat interesting or engaging.
The fact your list comprises solely of choices the player can make to make the default boring combat more interesting, instead of being a default of interesting like in other games. For instance, I gave an example of a RTwP game that has active, fun combat in Arklash Legacy. There are a ton of examples for TB games including ToEE, the new X-Com game, D:OS, Jagged Alliance Wildfire, etc.
YOU can choose how under or over powered your characters are going to be.
Why would I want to be underpowered to make the horrible combat better when the combat should be better? I can choice to gimp myself in pretty much every real crpg, but doing so isn’t a game feature
YOU can choose what type of character/s and specialisations you play.
Yes, this is one of my favorite parts of crpgs
YOU can manipulate a huge number of sprites during combat.
How is this unique to the IE engine?
YOU can choose what actions are preferred in any given encounter.
How is this unique to the IE games?
YOU can choose you own personal and exact combat style/methods.
How is this unique to the IE games?
YOU can choose if you want to cheese or play with strict personal limitations.
I can do this in every game. Creating my own rules for a game to make the combat more interesting when the combat should be interesting to begin with is silly.
If a game fails to have fun and engaging combat, but fill the game with 90% easy, filler combat with endless hordes of easy, nonsense mobs, the game has horrible combat. PEriod. It is not up to the player to gimp characters and try and find fun where there isn't any to be had. My reason being are plenty of games have fun and engaging combat from the get-go without player made up rules or character gimping.