but C'mon these places really will be a test for everyone
and although I'm really looking forward to them I can't help feeling they will be the end of a lot of PvE boxers
Don't worry. At the moment, these places are run buy under-geared or just bear minimum geared people. Eventually, everyone (us included) will over-gear these instances and steamroll them.

Normal instances and heroics are not the only places to acquire the necessary gear, there will be reputation rewards, quest rewards an pvp gear.

Then, what does it matter that we'll lose /castsequence,,,, ? What does it matter when we eventually pull 15k dps with a /castsequence spell, spell, spell - when really 12k would be required to down stuff - and the optimum rotation would pull 20k dps? (DPS figures are examples)

WOW was, is and will be based on gear, not skill. And btw. don't forget what our biggest asset is: we are not surrounded by stupid people