Some suggestions for improvements, or at least for discussion between major releases:

• Read suspicious hosts from a file (done in scripts: Read suspicious hosts from a file instead of hardcoding #17823, removed completely in contrib: Remove suspicious hosts list from makeseeds #24862)
• Determinism could be improved (this is useful for cross-checking)
  • Read ASNs from a file (Done in contrib: Use asmap for ASN lookup in makeseeds #24864)
  • Per-ASN limit isn't consistently enforced?
• A max of 2 seeds per ASN seems a bit strict at lest for IPv6 (done in net: improve and address issues in makeseeds.py #24818)
• Should we bump MIN_BLOCKS? (done in net: improve and address issues in makeseeds.py #24818)
• Some typos in the comments
• Handle and hardcode TorV3 peers (after Complete the BIP155 implementation and upgrade to TORv3 #19954), see Hardcoded seeds for Torv3 addresses #20239
• Bring back onion functionality past TorV3 switch
  • We need a source of non-hardcoded V3 peers, currently the only ones are hardcoded and the seeder hasn't been updated to crawl v3 nodes yet (see crawler: Collect Tor v3 and I2P addresses? sipa/bitcoin-seeder#92)
  • Consider increasing uptime requirements for Tor nodes from 10% as there appear to be enough

#7398 was a previous attempt to improve this script, but was abandoned, maybe some changes are useful.