If you're talking about a rate of 500K in less than 1 second ... yeah, you may want to find out where all the (re)compilations are happening.
If you're talking about a rate of 500K per minute ... probably not a big deal.
If you're talking about a rate of 500K per hour ... I wouldn't worry about it.
NOTE: Just re-read your post ... 500K/s(ec) ... so yeah, that sounds pretty high if that's a constant rate.
Also, depends on the number of queries, complexity of said queries, and volume of stats that have to be perused during the compilation phase.
Keeping an eye on procedure/statement caches is always a good idea ... sp_monitorconfig for proc cache high water mark; sp_sysmon for performance stats on proc/stmt cache usage is quick/easy if you don't already have an infrastructure setup for sampling/storing/analyzing MDA tables.
Reducing (relatively) high sysstatistics ios comes down to a) reducing the number of histogram steps that have to be processed by the optimizer and/or b) redesigning your SQL inventory to reduce (re)compilations. The latter could be tough to do if you're seeing a lot of exec() calls, procs 'with recompile' and/or dynamic-proc/lightweight-proc creations (eg, prepared statements).