Magellan dealt with BB Pirates himself when he let Shiryu out. Shiryu is weaker than Magellan and it took the combined might of the entire crew to take down Magellan. Shiryu was never called Magellan’s equal just that he was feared because he was strong but willing to kill prisoners for fun.
BBs bounty was 0 at the time. Pre timeskip bounties for their crew means nothing since they were trying to keep under the radar.
He wasn’t one shot material for ace; he just wasn’t on Aces level. Post timeskip Burgess was shown to have ryou and insane physical stats.
I just don’t see any other reason for Burgess to be the first captain if not for strength or because Oda plans to make him the strongest. He made Shiryu number 2 why not just make him 1 if he’s Blackbeard’s strongest?
BBs bounty was 0 at the time. Pre timeskip bounties for their crew means nothing since they were trying to keep under the radar.
He wasn’t one shot material for ace; he just wasn’t on Aces level. Post timeskip Burgess was shown to have ryou and insane physical stats.
I just don’t see any other reason for Burgess to be the first captain if not for strength or because Oda plans to make him the strongest. He made Shiryu number 2 why not just make him 1 if he’s Blackbeard’s strongest?

With Impel Down earning its impenetrable fame thanks to the combined strength of both Magellan and Shiryu:

And Magellan originally planned to free Shiryu to stop the BBP but Shiryu ignored the orders and helped them later on because he will be executed anyway:

Even Teach compared his presence with Magellan himself:

The only reason why Teach's bounty was 0 is because he layed low during his time on Whitebeard's ship. The crew members were active before joining, Laffitte was stated to be a notorious West Blue criminal who was recognized by Tsuru, all of them earned their own epithets. "Champion", "Supersonic", "Demon Sheriff" and "Death God". so they were still known pre timeskip.
Pre timeskip Burgess was irrelevant in the fight that Teach was worried he would get caught in the crossfire against Ace, post timeskip he barely showed anything that places him above Magellan, let alone DF Shiryu.
This is from Burgess' Vivre Card:

If the ship number indicated strength it would have been mentioned above.