Our shaman would be delighted if this were to happen (poor lass gets overworked and is always the last one buffing
) but the balance between Rk. I and II being single to group is important. I think it's more than enough that we can use T8 spells at level 70 pre-raid and, for many spells, there's a T5 equivalent that is group target and not that far off of the Rk. I version.
What I wouldn't mind is a couple more T5 equivalents that aren't quite as nice as Rk. I but are group versions. For example, True Thoughts for the Enchanter, sat between Chaotic Thoughts and Insight Rk. I gives you an improved group target version of the previous spell that's slightly weaker than the single target Rk. I spell. True Thoughts isn't significantly weaker than Insight, so it's something we'd consider if our Enchanter was taking too long to buff. We don't use it but that's because the Enchanter isn't overloaded when it comes to buff time (particularly given the Shaman takes ages anyway), so gladly take the hit and get the benefits of the Rk. I spell. This is good spell design, in my opinion.
Spirit of the Panther Rk. I doesn't have a similar spell (previous is Spirit of the Panther which is also single target). So a spell like "True Panther", which is say 200 dmg 400% procrate but group (bridging 175 and 275 dmg) would be something I'd consider using instead of the Rk. I spell until T8.
Similarly, there's actually no previous version of Gladiator (that I know of... Champion and the Might spells aren't the same line and stack with it). So a group target spell called something like "True Contender", that gives +20% chance to trigger critical dot, critical nuke and +20% physical damage (instead of +27%), would be something we'd definitely consider using instead of Gladiator Rk. I under many circumstances.
There might be more examples like that, though the only class that I think really suffers with the single target buff limitation is the Shaman, due to the number of buffs they get, and those two spells are the only ones that we really have to use sparingly due to the impracticality of casing them on every raid member, that also don't appear to have a "True" group version. We don't even bother with Lion much at all, it just takes too long to cast on top of Gladiator and doesn't last long enough.
So if there was going to be a change, I'd vote for something like that. Two new spells for the Shaman, T5 group versions of Lion and Gladiator, that are less effective but save a load of time for the Shaman when buffing and would be more than suitable for T5 to T7. In this case, we might even consider using True Thoughts instead of Insight Rk. I most of the time, as well - our buff times would be significantly reduced but we'd still be more than competetive at our current tier.