I'm honestly not sure how to respond because it seems like it already does what your asking for and the examples you give are things that the current idea is already doing. I mean I mentioned that Garuda and ramuh would add dots to make use of times when you had to move, you'd plan for that or have those built up on standby for when you need them. But you said dots aren't useful in raids. The spells that you use to build up the summons makes you alternate with the procs as their main function along with just doing damage but for me, having some be very different then others is what would make it an easy job because that is when you simply learn rotations and don't have freedom anymore.
I just don't know if we will agree on one thing, that using whichever spells you want to build whichever gauge you want will lead to a set easy rotation. In my opinion, once you start adding in things you need to do and upkeep you gotta follow, that's when it becomes a non thinking job and takes away the freedom. The examples you mentioned specifically blm and rdm are similar to how it is now where you have to keep your movement spells ready for when you need them (Blm), in this case it's not spells it's the summon (Garuda/ramuh) and their abilities that are easier to use when you gotta move because they add dots. For rdm you aren't trying to keep from being unstable in the smn job but you are making use of procs that take you around the elements.
In rdm's case it's only 2 elements, in this case it's 6 and although it's not random which ones you will get, it still allows for planning and control along with a way to cycle around to all the elements if you choose or focus on just 3. Because you are cycling 3 at the minimum that would mean that you would have at least 3 summons ready to go at one time, that's the choice, it wouldn't be build up one bar enough to summon then start from scratch on another one. Having that reserve of summons and using them when you need to is the quick decision making your asking for. It's just not your standard spells, it's your summons.
Having the elements proc randomly is fine but I think that would make it too random and not allow you to control which summons you want anymore. Like if you are trying to build Leviathan fast but the spells just won't proc water that takes away the strategy. It's also fine if the regular spells can have some specific things like dots but to me that also makes it more of a standard rotation kinda thing because now you aren't choosing to use that spell to summon that primal your only using that spell to keep its dot or status effect up.
I think your seeing the smn spells as what should keep the combat interesting as far as the differences between them but they are simply a means to the real meat of the job. Similar to how blm had to stack astral fire 3 or umbrella ice 3 to make full use of those fire or ice spell powers, you build stacks and you can then use better spells that only come from the third stack. It's similar in that way. It's not a perfect job since there are no complimentary actions to speed those up and the timing of things aren't set to get the exact feel of the speed of combat but it's not having 1 decision every 30 seconds, it's having many options available to you at once and when you use one option you have to be prepared to not use that again for at least 30 seconds. If you using one summon but suddenly need another you could dismiss early to quickly summon another that you already had built but then those 2 would be on cool down back to back sooner then normal so that could leave you without 2 summons when you only would have had 1 on cool down.
There's risk/reward in that way too.
I'm open to any ideas I just think that anything that forces you to do something to keep up dps is what makes the job have a set optimal rotation that everyone will just use that. I think what your asking for is leading to what you don't want but maybe we just don't see eye to eye. This isn't meant be be any sort of disrespect towards your ideas, I just think we don't agree on what the problems are