Britain is ejecting hereditary nobles from Parliament after 700 years

It can still do the same thing without hereditary peers. A slow-moving, conservative (in the classical sense) upper chamber is a classic in bicameral systems, it is not specific to the House of Lords.

Different common-law countries have addressed this issue in various ways. Restricting jury trials for more serious offenses (in this case for more serious charges - ones that could potentially result in a sentence of more than 3 years) is one way than many common law jurisdictions have taken.

It's not ideal but it's infinitely better in my mind than the practice used in the US to reduce jury trials. To avoid the cost/expense of a jury trial, public prosecutors threatens to press for a large number of charges or some very serious charges - carrying the potential of very long sentences - a sort of Gish-gallop approach.

Even if the chances of successful prosecution is relatively small for any one of the charges, the defendant is forced to take a plea-deal to avoid the risk of spending years or decades behind bars. Thus the defendant ends up with a guilty record and often a custodial sentence without any access to a trial or the chance to present their case at all.

No. As you have surely seen, the US written constitution just gets contorted to "clearly" mean whatever it is the partisan Justices decided suits their current purpose. The effect is extremely corrosive - they even decided it means their guy is above the law.

I agree that using a better voting system (STV) is a meaningful benefit and worth replicating elsewhere, but I don't agree that having a written constitution is better. I think Ireland would be in roughly the same place if it had the same arrangement as in Westminster in that respect.

For example when Ireland wrote a constitutional amendment saying abortion is illegal under basically any circumstances, the people the Irish were electing would also have voted against legislation allowing abortion, but by the time the poll was held to amend to say abortion must be legal, the legislators elected were also mostly pro-choice. So if there was no written constitution my guess is that roughly the outcome is the same, in 1975 an Irish woman who needs an abortion has to "go on holiday" abroad and come back not pregnant or order pills and hope they're not traced to her, and in 2025 it's just an ordinary medical practice. Maybe the changes happen a few years earlier, or a few years later.

Edited: Clarify that the abortion prohibition was itself an amendment, as was the removal of that prohibition.

It’s also very brittle and one charismatic populist away from unraveling like the American government. Too much depends on gentlemen agreements and people trusting other people to do the right thing. It works in a stable environment, but shatters the moment someone with no shame and no scruples shows up.