Here's one way to look at it
LoR5 vs LoR1: 11/7 = 1.5714, this represents a 57% increase in output.
LoR5 vs LoR4: 11/10 = 1.1, represents a 10% increase
Your options in healing are limited. For situations where you have to heal you have mostly two abilities are your disposal. That is Healing Wave and Land of Recovery and a 10% increase sounds pretty appealing. The same case can be made for cold bolt(or most abilities really) though so it is up for you to decide on more healing vs dps. The two points you have in CB has several alternatives and just simply boils down to personal preference.
In my opinion though, most PuG/Random groups are dumb and don't notice details. They won't notice how potent a spell is, only if it is down or not. I'm pretty sure Sorc players could get away with 1/5 deluge, earth seal, and LoR and go full dps and if there was a wipe due to healing everyone would be looking at each other stupidly going "WTF, what happened?" cause in the end it falls onto the Priests' shoulders from what the playerbase assumes. Sorc could easily say LoR was down and Deluge was dropped appropriately and players would simply nod and say "ok". A bit underhanded, but that's simply my opinion. I wouldn't suggest doing this though cause quite often you could find yourself in a situaton where the Priests are dead and you end up saving the attempt cause you do have healing potency. But unfortunately that still doesn't help make the case that Sorcs can heal to the wide community.