Will this make RDM more desired and useful? Dunno. Seems like anytime we find content that is difficult, an optimal solution is found, and that gets used, and then if some jobs don't like it they complain that there is "abuse" because their job isn't part of the optimal solution, so our nice things get taken away. If RDM happens to be part of that optimal solution, great by me. I have a 99 RDM character. If not, well it will probably be nerfed anyways due to complainers in the future who feel left out.
The problem presently is not overly job design, job ability, or content difficulty. Optimal is applicable in the minority of group encounters, and really only applies currently to a handful of events. I would say presently NNI is the forerunner there. But if you look at events such as Abyssea, or Voidwatch, they are by design limiting in their involvement. RDM for example is simply not needed in either event because it offers nothing that can be perceived as required. Voidwatch in particular is very unfriendly by design especially to RDM.
This is why I say the mechanics need to be looked at, and not just the event mechanics such as the proc systems of Abyssea VW and even Dynamis. But the systems that got lost in the move to a 99 cap. Specifically for RDM the enhancing and enfeebling skill systems that do not really benefit having higher skill than other jobs. WHM and BLM are landing enfeebles as well as RDM in nearly all cases, and the jump to T2 enfeebles is hardly worth writing home about. The fact that through subbing RDM any job with native MP is essentially going to be as effective as RDM in a buffing/support role also hinders the jobs requirement, and more over the fact that WHM over shadows it in terms of party buff utility, despite having weaker Skill levels is just another dagger in the back.
Simply adding more things on top of broken mechanics does not fix the jobs, it does not make them more desired or even required. What needs to happen is SE needs to address the fundamental flaws within the mechanics of the game. They did this somewhat with Healing by ensuring native healers will always be able to push higher numbers based on their skill levels than those who do not have such skills (such as SMN/RDM, or BLM/RDM or what have you.) They need to do so similarly for Enhancing and Enfeebling magics, RDM should be capping these types of spells higher than other jobs, not sharing the same caps as jobs with much less skill than them. RDM should be landing stronger Paralyze I than a WHM, and it should be landing stronger Hastes than a /RDM a /WHM or a WHM. The skill mechanics need to reflect the differences between the jobs, more so than they do now. Otherwise certain jobs, such as RDM in particular will never be seen as worthwhile for anything but a subjob option.
As for Haste 2, it is hardly a requisite, unless of course SE is going to be altering the caps for haste, which again ties into my distaste with their approach to the mechanics of the game.