Though the fact that everything will be multicombat does make it somewhat better than it is now. In terms of RuneScape gold herblore, Mod Pi is a good choice. With respects to prayer and herblore and prayer, the current in-game bonuses that the highest levels offer pushes the player over their level that it was making managing bosses hard.

If you had balanced for a player without these boosts, players with more than turm + Ovl would find the battle to be a walk in the park. If you were balancing for players that has these boosts, you basically made them a requirement. This isn't the ideal situation because the boosts prayer and potions offer should be seen as an increase in what you have rather than more important than having the most powerful weapon available in game.

However, with their current strengths, turmoil is capable of giving you the same boost as difference between barrows and nex gear and chocs. Overloads can give you an identical boost to the differences between Godwars Gear and the nex gear/chaotics. This means they're not tiny boosts.

I can see how compared with the current state of the game, these appear to be huge nerfs however the problem is actually that turm/ovl is at a high level and has been in that condition for too long.

I'm thinking that when the cb update launches summoning will not be as useful as herblore. However, after the overhaul of summoning, it's going to improve.

Ignoring everything else I'd recommend using the xp on summoning as it will benefit more out of the bonus xp because you'll save money and time in gathering charms. Have you noticed that previously summoning would always have the 1.1x multiplier for weekends of bonus xp unlike other skill types, in order to be unbalanced? Well, this time it's exactly the same as every other skill, so I'd make use of it if I had to buy runescape 3 gold summon to gain xp.