Absolutely it could happen, but it would be far more likely that they would just take the ride out and replace it with a different, maybe similar experience. TNT was produced by Arrow Dynamics as one of the last mine train type roller coasters the firm ever built before going out of business in the early 2000's. This type of coaster is actually what catapulted Arrow into becoming a giant in the roller coaster industry. They built dozens of these things around the world, but SDC's was probably the last and greatest of them all (most of them were pretty boring honestly, so it's not that big of a compliment).
Anyway, the point is that TNT is part of a legacy that has past on. The park has made a lot of effort in keeping the ride up over the years, but it is still a bit rough and of course the layout is now overshadowed by the rest of SDC's coasters. Arrow Dynamics was purchased by S&S Power (the company responsible for Powderkeg and TGS), so parts are still available, but the practicality of renovating and/or extending the ride on top of what currently exists is minimal.
With the new coaster that is coming to the park, TNT may become upstaged and with the passage of a little more time management may feel it warranted to finally replace it. In 2004 it actually sounded like they were looking into the possibility of replacing it with a new mine coaster, but luckily they choose to replace Buzzsaw Falls instead.
I don't feel like I would miss it too badly if they went ahead and replaced it with a new mine coaster in the same spot. It holds a sentimental place for me, but it could be so much better, and now without the backwards facing cars it has lost a bit of what used to make it special.