I'm a Sroc healer (Mostly PvE Raiding)
I just want to say.. Who the heck cares about DI... really. DI is my "oh s#(@" heal when the MT is hovering at 10% and i need a lucky crit to get him back to a manageable level
otherwise I NEVER use it in my regular rotation.
my raid healing rotation is
resurgence -> innervate -> consumption (repeat)
during the 9s cool down while i wait for innervate I throw out static barriers or throw at a revivification (purple circle)
DI to me is last in my bag to be used.
why such adherence to the rotation? because that's the only way I'm going to be able to have enough force to endure the fight. If a sorc healer breaks the rotation for too long you bottom out.. and there is no "Pop a cool-down to gain half your force bar back" ability for sorcs. The only way to restart the system is to spam consumption on yourself (draining a chunk of your health) so you can restart the cycle and get the non-punishment consumptions form innervate cirts.
TLDNR:
The fact is the OP has never healed as a sorc and tries to compare apples to oranges.