I think that the concerns here regarding the competitive advantage of young vs old shards are well expressed. I think that it should be possible to address these concerns by scaling the core progression statistics based on each shard's time dilation.
Base resources scaling could be something like y = 2 - 2/x so that at a 2s tick there is no benefit but the bonus is not linear (encouraging DoS).
For example, if with 3 shards exist: A (the origin, 5s tick), B (first new shard, 3s tick), and C (brand new shard, 2s tick) then the benefit to several resources should exist:
* GCL gained on an account might be scaled up per y = 2 - 2/x. Shard A would contribute 60% additional GC per RC, B would contribute 33% additional GC per RC.
* Power processed could have limited scaling perhaps on the function y = 1.5 - 1/x. Shard A would contribute 25% additional Power per Power processed. B would contribute a 16.7% bonus.
* The 5% market surcharge may be reduced to y = 0.05 * (0.5/x +0.75). Shard A would charge 4.38% on market orders. Shard B would charge 4.58%.
CPU expenditure would not be affected.
There's probably some edge cases I haven't considered, but scaling of this kind would slightly blunt the advantage players get from aggressively populating new shards, and provide some incentive to spanning new and old shards.