RE: AS PATH limits

The consequence of keeping a route with a long AS_PATH is that it uses a little more memory.
Also, if you send it on, you will add one ASN and may exceed the maximum BGP message size and not be able to send it.
Even that is no reason to drop the incoming route.
The consequence of dropping the route is that someone loses connectivity because you dropped it.

The need for limiting AS_PATH length stemmed from this incident:

This bug has long been fixed, so it should not happen again.
However, if you want to be extra cautious, because unpatched routers may still be out there,
then 200 should not drop any normal route. Just keep an eye on what you are dropping