Look, if you don't like RAs, there are several ways to fix it in mods. Here are a couple that have been done so far:
1> In Thalassicus' "Vanilla Enhanced Mod" (by far the most popular Civ5 mod in existence), he tweaks RAs to give a larger number of beakers to the civ with the lower number of techs and a lower number to the tech leader. This generally makes RAs a good "catching up" mechanism for the folks who've fallen behind, and not something a tech leader can use to maintain his lead.
2> Long ago there was a "Tech Diffusion" mod that mimicked the Civ4 method, where a civ would get a bonus number of beakers each turn if they were researching a tech that other civs had already completed. I know, this is not really about RAs, but it definitely changed the appeal of those, as you didn't have quite the impetus to gain techs at all costs.
3> Quite a few mods adjust RA costs directly. In my own mod, they're basically doubled. You see, the AI's decision process is purely probabilistic; there's no ability to create long-term plans. So what happens in vanilla is fairly straightforward; let's say the AI has X gold (the amount needed to buy the RA). Its choices at that point are basically: bribe a city-state, rush a unit, rush a building, enter into an RA, buy a resource from another player, or do nothing and save it up.
The problem is, the default value needed to buy an RA in any given era is almost always significantly lower than the amount needed to rush the units or buildings available in that era. So what happens in practice is that the AI will spend at least a half-dozen turns deciding between "enter into an RA" and "do nothing" before it reaches the point where any other options are available; even if the odds of picking the RA are low, there are just too many opportunities to do so over those half-dozen turns, so the chances of it actually saving up enough gold to rush units or buildings are very low. In practice, then, you see a bunch of RAs.
Now, what happens if you increase the costs of an RA, say by doubling the costs across the board? Suddenly, the situation is reversed; now, rushing a unit or building is cheaper than an RA, and it's much more likely that the AI will "pull the trigger" and use the gold to rush something instead of saving it up for an RA. You'll still see RAs fairly often, since the AI will be much more likely to make a gold-for-resource trade deal with another AI and get a sudden influx of cash to jump above the RA threshold (or enter a Golden Age and get cash faster), but it won't be the sort of all-consuming cycle you see in the vanilla game where each AI player will enter an RA as soon as any other civ has enough spare cash.
In my own mod, this is exactly what's happened. You'll see a few RAs, but if a civ is in a war it's far more likely to spend any extra cash on an extra unit that it desperately needs, which means it won't save up enough to participate in RAs. It's proven to be much more balanced in practice.
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Now, what really needs to happen, IMO, is to tie RAs to other diplomatic functions. Imagine, if you will, a scenario where you can only enter into an RA with a civ with which you have an active Declaration of Friendship, with all of the diplomatic effects that implies. Suddenly, it becomes much harder to have multiple RAs running simultaneously. But this sort of redesign would require the DLL, which we don't have at present.
