I believe the concern between traditional and modern muzzleloaders is a legitimate one to talk about. I am all for whatever it takes to get people more involved in shooting, hunting, fishing, camping, etc. It's all good, when it comes to exposing more of the public to the "outdoor sports".
However,hunting is by it's very nature, a competitive game. We compete against our quarry. We compete with each other. There have always been inequities in the hunting world: the guy who can afford better equipment; the guy who can afford to hire a guide, the guy who has access to private land; etc. We generally accept this and play the cards we are dealt.
But at some point, we all have to recognize that the inequities have become so great that the playing field needs to be leveled a little bit. That is how we got a muzzleloader season separate from the high-powered rifle season in the first place. Modern, in-line muzzleloaders are a natural evolution....they take it to the next level. But I think it is a valid question to ask if it has not reached a point where the playing field needs to be leveled once again.
Today's modern, in-line muzzleloading rifles have the ability (faster twist barrels) to shoot sabboted rifle bullets. These bullets have better ballistics and perform much better on game than round lead balls. Most have the ability to mount scopes that not only magnify your target, but have BDC stadia to help you compensate for elevation drop. Compare that to open iron sites and Kentucky windage. Their ignition systems are superior and are often protected from the elements. Taking an elk at 250 yds is unheard of with a traditional muzzleloader, but entirely possible with a modern in-line.
As has been pointed out, we have a similar situation with modern compound vs. traditional bows in the archery world. It would be nice if each weapon type could have their own season (Colorado for one, mandates iron sites for their traditional ML season). But in reality, most states do not have the luxury of hosting that many different seasons for each species of animal. Perhaps designation a few hunting units for traditional ML and archery seasons is one answer.
While most of us don't always have good solutions, we can all acknowledge that a problem or inequity exists and start a dialog to find answers. Ignoring the problem because "we don't have a horse in this race" is foolhardy, at best. As I look to the horizon, I can see other clouds gathering. It could be fellow firearm hunters who now feel that LR hunters with their rangefinders and custom guns possess an unfair advantage and want to level their field as well.
In helping others find solutions, we just might be helping ourselves.