As for the speed, my home internet connection is very fast now but the blockchain downloading (syncing) was VERY slow. My download bandwidth was being used at 2-3% only.
Core downloads blocks from many sources and it is comparable to a torrent. The downloading itself is fast but the validation process is very slow. Its not a problem with the internet speed but rather, your hardware speed.
It seems to me, you are not quite right here.
When my Bitcoin Core 0.14.2 was syncing itself (downloading the blockchain), I saw the bottleneck was precisely in an insufficient number of other full nodes that accepted incoming connections, from where my node could download the blockchain data. As memory, processor, Internet channel, all they were busy for only 2-6%!
You compared to torrents.
OK, when I started any popular torrent on the very same computer, then the whole my 2.5-3Mb/s download bandwidth was immediately busy at 100% (ram and cpu were of course still almost free).
But if I started a rare unpopular torrent then it would be similar to syncing the blockchain as of June this year - very slow indeed