I think there probably are solutions or at least partial solutions (which can be enough) to most of the issues you mention.
Let's put together our dream leagues just for lols. Here's my drastic, ridiculous ideas:
1: Local qualifying leading to one major nationals.
2: Reworked basic game format. Some kind of objective. Touchdown lines, offense and defense, whatever - a format that gives something close to a focal point being the goal. Preferably not complex. Ideas here. Have tried some of those ideas. Mostly they work, would need tweaks.
3: Mixed markers. Meaning: of a five man team, only two are allowed hoppers+electro. The rest max out at 30 round magazine fed, and maybe even one with just a pistol. 10bps limit but no firing mode restrictions for all. Why? It massively decreases paint usage and cost for most players, allows other players to play full noise and spend $$ which keeps the adrenalin up, makes reloading a bigger tactical issue, encourages freer movement, sells more guns which is good for the industry (most players will want all three types, there's an inbuilt natural progression here) and most importantly helps bridge the gap between the types of paintball. The tech would filter everywhere. Of course it brings an admin load, but I'm making the case that it'd be worth it
4: Respawns - save elimination for power plays and tiebreakers. Why: More game time per player, including those who get shot a lot. More relevance to gaming. More commonality between the types of paintball.