Hello,
there are plenty of ideas about setting higher level cap. I see positive and negative effects of that. Positive is that you would encourage one char playing, creating stronger connection between player and its avatar, also you would need more time to level it up, so you can play this game longer. Negative is that every chars would be very similar, if you dont nerf perks, it would be harder to balance the game (imagine lvl 36 PK in mnes VS lvl 5 noob).
But one negative element of current system is alting. So why not find other way, how to encourage signle char players, or at least one dominant char players. You can create your main battle char in four hours (big gunner with enough ammunition), or few days and irony is, that this "fast food recipe" is tastier than "long time cooking".
My suggestion finds solution in quite different aproach than the whole leveling is based on. But it is not non Fallout compatible idea, as you will see. Current leveling will stay, even the level cap and level speed, but there will exist ways, how you can boost your char or add another advantages.
a) minor perks
You can get minor perks as a reward of quests of achieving some tasks. It will give only minor benefit, that will not absolutely ruin the balance but can be reason to play longer, even if you have nothing to do (all quest finished,...)
Quest that if you clear 100 caves, you will get bonus +1 to perception in night.
If you mine 250+ HQ resources, you will get +25 weight capacity.
If you domesticate 250+ brahmins, you will get free pathfinder perk.
If you cure yourself 100+ times poisoning, you will get +20 HP.
....
b) combat perks
Combat perks could be group of perks, with special purpose. eliminate the difference between powerbuilds and a loner. If you want to play PvP, you have to spend all CH points somewhere else. If you are "classic player", you need at least 3 CH, or even more, if you are slaver, brahmin hunter... .
So why not add quest very similar to previous ones (kill 1000+ floaters or something else), where you will need charisma bigger than power build can have without drugs (7-8 CH, so 5 basic + 3 with drugs => no problem for classic players), and if you finish that "quest", you could get a free perks that will eliminate the difference between power build and "classic build".
The practical difference will be, that if you want to create power build, you will have to spend 8 hours or few days, if you want to achieve those bonuses by "classic way", you will need weeks or months.
c) crafting traits
I like weapon customization. I suggested it somewhere else, but crafting roleplay is very boring. You can be small gun crafter at level 4 with skilled trait and 10 IN. I dont like idea that you need luck to craft, it will not solve anything: you will spend points from other SPECIAL attribute, or you will have your char ready at level 5.
So why not support "classic players", with ability of giving traits to weapons. At first, they will have to craft at least 10 (20/50?) weapons from the crafter list, then they will have to finish some quests, maybe kill some amount of NPC. This will eliminate possibility, that level 5 crafter will have same abilities like crafter roleplayer.
Example of traits: -4 max damage + 4 to min damage = more constant damages,
+2 damage to human based enemies, +1 AP needed to shot
- 25 percent of weigh, -33 percent of ammo capacity
- 25 percent damage to players(humans) + 15 percent damage to critters (supermutants)
This traits will not ruin balance of game, but it will make crafting more individual that it is now. Also there will be bonus for classic players, instead of gangs factories. It could create relations between gangs and basic players: "Looks, that gordulan mining, he is good crafter, dont kill him in mines, he will not sold you his boosted sniper rifle."
So what do you think? Additional perks/traits were in Fallout 1/2 game too.