After re-reading all the comments I think you are concerned with the wrong thing. You've mentioned that people in lower ilevel are punished more by colossus smash, when that's not even true. If anything, more powerful gear actually makes colossus smash even more important.
Now, with the following pictures you'll have to ignore the dps numbers. Unfortunately, the ability to add in custom reports for simcraft wasn't added until our WoD-branch, so I can't make them appear in MoP. However, our rotation is effectively the same, so the percentage of damage done inside of CS will still be accurate.
First, an example of someone who is fresh out of leveling, 460 ilevel.
http://gyazo.com/372de524d801ee10bf998a98a2c4e706
% Damage done inside of colossus smash: 46.28%
Enrage uptime: 66.01%
dps: 5150.19
500 ilevel, effectively what ilevel new players start at with timeless isle.
http://gyazo.com/01ef35ade1f3666bd0d5aa9418bf13a9
% Damage done inside of colossus smash: 48.18%
Enrage uptime: 70.88%
dps: 6964.51
540 ilevel, which is what flex will give you
http://gyazo.com/ef05449472d3e8b3a93f77d50af48d42
% Damage done inside of colossus smash: 48.63%
Enrage uptime: 77.60%
dps: 10323.40
Finally, BIS heroic:
http://gyazo.com/3ce9156ddeb42e5fcb0c3cbd343b4152
% Damage done inside of colossus smash: 52.24%
Enrage uptime: 88.33%
dps: 18372.26
The next set of pictures are what happens when I lower the skill level of the player. What simulationcraft does is it will randomly misfire on the action list, skipping lines, ignoring others, resource capping, etc. I've set it at "Average" skill level, rather than elite. This shows how much dps is lost when the player is new/bad/lazy/etc, and also helps us when considering how important colossus smash is. If it were more important at lower ilevels, then there should be a larger percentage of dps lost from people mismanaging it.
460 ilevel:
http://gyazo.com/7f02efb5f858eafb4e9a9fd3757cf749
4666.21 dps - 9.3% dps lost
500 ilevel:
http://gyazo.com/dae1b173882538b4551f355aa89727ca
6291.76 dps - 9.6% dps lost
540 ilevel:
http://gyazo.com/d9758271fde301f4c817481c4b91d8a8
9285.55 dps - 10% dps lost
BIS:
http://gyazo.com/802c54829b16e67ab540f466bae65658
16483.40 dps - 10.3% dps lost
If anything, colossus smash only becomes more important as ilevel goes up. The amount of damage that is forced inside of CS increases, and the amount of dps lost from mismanaging parts of the rotation goes up as well. Why is this? What changes with more gear that makes colossus smash more important?
What difference would more gear make with colossus smash? More gear gives additional crit, haste, mastery and strength. Strength, mastery and haste do not change our rotation whatsoever, with strength/mastery making numbers larger and haste being nearly invisible.
Crit? Now that's a completely different story. What ends up happening with high levels of gear is that management of raging blow charges becomes more and more important. At lower ilevel, you honestly get a free pass on raging blow because it's near-impossible to not use all of your charges efficiently when there are so many open globals. Higher ilevel grants more raging blows, which means less gcds and more opportunities to screw up by wasting procs.
At lower ilevels, you can hold on to 1 rb at all times to ensure that it's usable inside of CS, as the likelihood of getting multiple bt crits back to back is low. With 90%+ crit on bloodthirst, that's just not possible. You have to make more difficult decisions, such as delaying BT or chancing that colossus smash will crit when you already have 2 rb charges. Especially if you want to make any use of bloodsurge, which is still semi-important.
Mastery is a part of this as well, berserker rage goes from "Eh, just use it to make sure that colossus smash is enraged" at lower ilevels to being an incredible dps loss (Relatively-speaking) if used for any other purpose than ensuring maximum enrage uptime. When enrage is a 60% damage increase, not being enraged is big deal compared to 10-30%.
I think that the issue here is that players are placing too much emphasis on colossus smash, when 55% of your overall damage is done outside of colossus smash. Maybe this is an issue with guides around on the internet, as colossus smash IS important, just not as important as it's made out to be.