Peter said:
"In any case given that SPV peers don't contribute back to the network
they should obviously be heavily deprioritized and served only with
whatever resources a node has spare."

This seems very much like a "cut off your nose to spite your face" solution.

SPV peers are INCREDIBLY IMPORTANT to the growth of Bitcoin; much more
important than nodes that have the bandwidth and disk I/O capability of
being a full node.  Bitcoin will be just fine if there are never more than
10,000 big, beefy, full nodes forming the backbone of the network, but will
be NOTHING if we don't support tens of millions of lightweight SPV devices.

Ok, that's an exaggeration, Bitcoin would be just fine in an Electrum model
where tens of millions of lightweight devices rely 100% on a full node to
operate. But I would prefer the more decentralized, less-trust-required SPV
model.

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Gavin Andresen