You'll never guess what I found in a res the other day...
a wanted asp after hundreds of reses!, a 60k bounty asp, not just a accidental 400 cred one.
that must mean they are in the spawn pool, but maybe at 0.01%.
think about it though, res sites aren't actually for collecting bounties, they are for the miners.
and if you've ever mined you don't want the big ships turning up all the time.
weve all got to get our electronic crack somehow and some cats like to mine.
but I totally agree, its all very predictable when they do spawn. ( apart from the asp I mentioned

)
fingers crossed they'll sort something out later on down the line when they get back to the spawn tables and make it a bit more random.
if <one trouser leg rolled up> then spawn <vulture/python/dropship/clipper>
good luck.