Since the ARM11 is so old, it will be tough to find a direct comparison. The first ARMv7-A core, the Cortex A8, supposedly executes 40% more instructions than the ARM11 at the same clock speed.
http://www.anandtech.com/show/2798/5
The A9 shows 50% performance improvement over A8.
http://www.arm.com/products/processors/cortex-a/cortex-a9.php
You can follow the rest of the trail over at the ARM website. The A7 is slightly lower performance than the A9, but much more energy efficient. The A53 boasts a 30% to 50% improvement over the A7. This is all at the same clock, so yeah, if they go w/ a quad core A53 at decent clocks, we would be looking at a considerable leap.
Someone can correct me if I'm wrong, but I believe in-order vs out-of-order is something which mostly concerns your compiler. Basically, if they use the handheld as the baseline, they shouldn't run into any problems. I was thinking more about old Wii U code causing an issue, but that's nothing that can't be sorted out, especially considering the wizardry they are currently working w/ 3DS ports.