With the understanding that you know your players and their preferences best, every table has a slightly different social contract, and "internet advice" can only go so far, here are some thoughts.
1. Discourage bless+ GWM and SS
The real culprit here (if indeed one subscribes to the notion there
is a culprit), is GWM/SS. Bless is a good spell. Those feats can, in some situations, make it super.
2. Default array/point buy vs. rolling
If your group is more of the optimizing/Min-max variety, the default array/point buy tends to be more 'balanced' and fair. But this is can be a 'feel' thing for your group as well.
This can largely be a feel thing as well. The base game is supposedly balanced without taking feats + multiclass into consideration (or magic items), which may require more work on the DM's part to create challenging encounters, particularly as levels rise. IMHO, the feat design is not particularly well done, and they--along with multi-classing--feel kind of 'thrown in' at the end with a little bit of "These are optional, us at your own risk" type of feel. I've personally taken some of the feats and re-purposed them as abilities in Magic Items/weapons discovered in the game to some success. That said, many players feel very strongly that feats in particular given them the ability to customize their character and would be disgruntled at their omission.
4. Certain multiclass combos discouraged
As mentioned above, many like the 'build' option that multiclassing (and feats) offer them to get just the right character they want to play. In my experience, it usually turns into a min/max meta-game of optimization, which some might enjoy. But if the DM is not on board with that style can make encounter design more difficult. Many games try to enforce strong "in-story" reasons for multiclassing with varying degrees of success, but it depends on your group.
5. simply add CR to encounters
This is what many DM's do almost unconsciously, and it works to a certain point. It is understood that, as the levels rise, the more "inaccurate" the CR is anyway; due to the number of synergies and combinations and permutations available to the PCs
6. Limit the group to 4 PCs
I would be loath to turn friends away, but each group and DM has the limit to the amount of overhead they can handle I guess. This does seem rather extreme unless you are approaching 7+ players.
Lastly, this is not an indictment of the system or any style of gaming, at all. I just want more chances for players to feel the heat and do tactical retreats/high five one another after successes.
I want success to be likely, failure to be very possible with the dial or likelihood being moved by choice, incredibly good and bad die rolling excepted.
The plan would be to tell people up front combat is a "war game" and to treat it as such. In wargames poor reconnaissance and overconfidence can lead to custer's last stand. Don't be that guy![/QUOTE]