Firstly, why are the RDMs complaining about a SCH job ability...? You all complained about if we had the level cap as 100 and that Composure would be made subjob-accessible. Then go off and complain about a spell not stacking with something that, with the old level cap, was SCH exclusive? And does this mean that if a spell isn't Accession compatible, you'd rather not waste the time casting it? Ex; casting AoE Refresh I rather than Refresh II.
Secondly, if you honestly have trouble keeping a haste cycle going, lol. RDM is a support-role job in a party situation. At a time, it could main heal effectively, but that has come and gone. RDM (again, in a party/alliance role) hinders the target's actions while applying supporting magics onto allies and healing/nuking when they're primary role has been fulfilled.
Hastega isn't going to help this job. (And I loved RDM from day 1 of my time in FFXI) It needs a great number of things over Hastega... Cure V would be more useful than Hastega, but everyone's seem to have given up on that since the devs have very clearly stated no job, other than WHM, would get it. (Which, actually, if you take the time to get a cure potency + set for BLU, you're the second best healer in the game... Sub sch for -na spells and the healing skill increase.)
I agree that RDM needs some major fixes. And, from the looks of it, will be one of the last (if not already last) jobs to get patch-work done. But Hastega? Really? Leave it to SMNs/BRDs...