I don't think any of the issues above would impact the rate at which blocks are synced. But, anecdotally, it seems like we're getting about twice as many transactions included into blocks lately (i.e. more traffic). And that could lead to increased time to sync the latest blocks.

Also, as I may have previously reported, I've seen issues regarding the incorrect usage of concurrency primitives by the original devs that impact how the blockchain and p2p threads interact (on a performance level), and that needs to be corrected when we have some time.