Stat raises are fun because they give us a tangible way to represent the character progressing and growing in his or her most basic form: attributes. This is a legitimate goal to try and represent through game design. Stats are so fundamental to the game, though, that stat raises have the potential to do more damage than good. I believe that they do just that and will attempt to demonstrate this through the lens of combat and skills.
There is a dominate strategy when allocating any resource to allocate it where it will provide the largest benefit as often as possible. Very obvious. This dominate strategy is also present during character creation, which leads to characters with a single very high stat that almost all actions key off of. As a result, stat raises are concentrated into that single stat, pushing it even higher.
This strategy is so obvious that the game had to account for it. Over the 30 levels of 4e, there is the potential for any given stat to receive eight stat raises for a +4 modifier. That is 20% the entire range of possibilities represented on a d20 and too big a variance to not build into the math. So what we have is a wash: everyone gets higher attacks and higher defenses to keep the chance to succeed in that fun-tense zone.
The problem arises if someone decides not to follow the dominant strategy. If someone decides to increase non-primary abilities, they get some benefit, but not necessarily enough to keep pace with the game’s expectations. Over the course of the campaign they could fall 5 – 20% behind their party, hitting less often and being hit more often. This is punitive enough that most people take the path of least resistance (and highest reward) and follow the dominant strategy.
The end result is increasingly focused characters who become intensely focused on a single ability. Not necessarily bad, after all, people specialize all the time, but it doesn’t really feel like it achieves the spirit originally set out for: to represent the growth of the character.
Again, the game must take into account the possibility of a stat increasing by eight over the course of the game and so DCs reflect the dominant strategy. It makes sense that the super strong fighter (str 20) can jump farther than the rogue (str 10) despite the fact that they are both trained in athletics. When the DCs try to reasonably challenge the fighter with a 65% success rate, it feels fair that the rogue only has a 40% success rate; he invested in other places. But then the game coerces the fighter to invest in strength and the rogue to invest in dexterity and updates DCs. By the end, the fighter maintains a 65% success rate but the rogue has fallen to 20%.
Throughout the campaign, as the dominant strategy encourages characters to increasingly specialize, the net impact is that we focus less on what characters do well and more on what they can no longer do. What you do well is still reasonably challenging because we artificially set the DCs to ensure this fact, but what you don’t do well is now almost out of reach.
A simple change would get us back to the spirit of the original rule: stat raises cannot be assigned to your highest stat. Stat raises would still demonstrate character growth and actually reflect the character shoring up weaknesses instead. They would also still be really powerful but instead of one dominant strategy, there would be a lot of good strategies. During the campaign, it would actually tend to bring characters closer together with regards to skills. More characters would have a reasonable chance to jump over the pit. The fighter will still be the best, but at least his party can come along.
The epically bad downside is that it requires a reworking of the math because the dominant strategy is no more. This is relatively simple for things like DCs, but combat proves quite a bit more complicated. In the end it probably isn’t something that could be adopted into an existing game, but it is useful to consider in looking forward.