I disagree that SE limited the exping, but it was the players who did it. The game offers many camps that can be used to exp, but only the best ones are used. And there will always be "best camps" no matter what you do, and the players will go there. Only the mindset of most players was the limiting factor (although SE could have made few alterations to monster placement and location in some areas, which would have helped, although the problem would have still existed). In the end, players will only do what is the most efficient method, be it colibri, weapons in sky or campaign. There's really not too much SE can do about that.
As for not giving out exp for everything, that is again something that might not be an issue to you, but it is to SE. Players are already leveling "too fast", at least that's what SE seems to think, and they don't want to make that issue bigger than it is already. Make everything give out 20k exp, and players will catch up to content even faster than they already are, which makes them bored faster (nothing to do = quit) and they'll lose subscriptions. However, make the activities different from each other, and doing one activity will not make you finish the other activities. That means less playtime to "finish" the game, and for obvious reasons that's something SE wants to avoid.
It's not really a concern to you, of course, but from SE's perspective, it can't be overlooked