Poll responses are largely fueled by nostalgia. The desire to be a part of a group that grew in the era of certain combat strategies is the reason they desire to keep it going. However, nostalgia isn't a reason to take action. There are other reasons that you could choose to vote for the number 138 that aren't related to nostalgia. One of them is the familiarity. The 200 formula has been part of the game for more than 1 year.
Increase the danger in these forest areas. The majority of the globe is suitable for middle - to low level players. Barrows armour and dragons aren't common items to look at. The most hazardous places aren't always the most hazardous. This would be a huge increase in their danger when you include boss monsters into these forests. This is only feasible when the area is large enough that it's possible to get around them, if you know exactly where you are.
Make the in-game maps less accurate. If you could make it such that players had to go through each region before they could fully document it on the map, it would make a huge impact on the adventure feel. New lands would be truly alien.
Have fewer artificial barriers. This is a huge immersion breaker. If cliffs were scalable but took time and equipment, if boundaries weren't literally wooden fences that we could leap over, if rivers weren't actual walls, but rather obstacles that you could swim over if you had the proper equipment, that would be fantastic.
There are monsters, but they don't bind you to fights. There's training spots that they can use, however they aren't to be utilized. It's impossible to lose yourself to the beautiful landscape.