I could make my T-Engine games look *exactly* like my FreePascal games if I wanted to.
It does not matter whether you could give a classic look to T-engine games, because (1) in a powerful enough programming language you can do anything (you just need Turing completeness which many "simple" modding engines lack but any real programming language has, reasonable speed, and a way to interact with required software/hardware), (2) you need some work to obtain what is straightforward with FreePascal or Curses, (3) look is not everything, would you get ssh/NotEye compatibility?
From what I have seen, with T-Engine you can easily obtain something that looks like ToME (graphical menus that do not fit ASCII games, ToME running in background of the main menu), you need to partially rewrite this anyway if you want something else (opinions based on T-Engine games I have seen, not on trying to use it myself).
Having tried out both methods of operation I can't imagine going back to self-coding everything. Such a lot of hard work.
As Mosenzov says, if you do it right and do not want to try something different later, you only have to do it once. Consider Jeff Lait's 7DRLs. If you look at Sword in Hand, you will see things that obviously come from Jacob's Matrix, a closer source inspection finds things tracing back to You Only Live Once (and probably even to POWDER).
In the beginning of every roguelike, you usually have to re-create the same systems you had that most (not all) roguelikes generally have (Ex: Displaying tiles, picking up items).
For my next new roguelike, I would probably use the NotEye lib for displaying ASCII/tiles (unless I wanted something very different like in HyperRogue). But even such simple thing as picking up items can be done in many different ways. Hydra Slayer has a special inventory system (limited capacity for weapons, no equipment otherwise, unlimited capacity for potions etc, which come in just a few varieties and thus we can just count the number of each of them in the inventory, and assign them fixed hotkeys), and the UI is designed around this; I think it would make no sense to copy it from another game, or to hope that T-Engine's inventory management system is just what I want. If your two games are similar, that is good for you, but do not limit your creativity
Anyway, I think this is really subjective and experienced programmers will have their own impressions about which way of programming is the most effective and the most fun for them, and these impressions would be mostly right (the recent counterexample was a newbie writing a roguelike in Assembly, a bad idea IMO). I am not sure about newbies, but ToME fans would pick T-Engine, Angband fans would go create a variant, and so on. Although my knowledge about T-Engine is based only on several games I have tried. This allows me to see some common shortcomings and good features (you seem to get the ability of redefining keys comfortably for free, which is quite boring to program by self). It would be helpful for T-Engine to have an easily findable article pointing out which things are actually easier to do than with other techniques.