I'd have suited a grammar style education (bad seventies comp, failed but went on to do well at post grad level). I don't, though. I support good schools that have the ability to cope with all abilities. Segregation is a bad thing, children and young people learn compassion, gain empathy and widen their world view when they come into contact with others from different backgrounds.Many writers link EQ to long term success, and I don't believe that's easy to develop in restricted environments.
I'd back a campus approach, where schools have facillities for the brightest, average, academically struggling, and those with AN, but where they share communal spaces, and can move between streams as necessary. My third son's school runs something along those lines and it's a very calm environment that helps all children achieve and gain confidence.
For various reasons the three of my four sons who have reached comprehensive age (there are no grammars in my part of the UK), have attended different schools. They are fairly academic young people, the two with career plans set are aiming for animal behaviourist and psychologist.
I've seen different models in action but I'm not seeing kids left behind, a flexible system and gifted teaching helps prevent that. My eldest's best friend was too severely ASD for most grammars to consider, he ended up with 11 A* GCSEs and seems set for a good career in his sector (ecology).
Son2's school has a very naice, MN friendly intake but if anything has struggled the most- they also employ the least inclusive methods, keeping to a standard route of options at GCSE level and an academic path. The other two offered year 9 options randing from academic paths to BTEC engineering, drama and construction. My own son chose art and discovered a talent for surrealist painting that kept him engaged at such a crucial time.
Just because one system is struggling, it doesn't justify returning to a different system that failed many. It means looking at education nowadays and creating new, dynamic options. Nobody cared about those with SEN or brighter kids from very poor families (travel, uniform costs when no hand downs available- the factor that prevented my own 11+ passing dad from attending grammar), in the old system. I hope that we do now, and we recognise that kids have a lot to give in the ways that suit them, and that shouldn't be dependent on finance, disability status, or an exam at age 11.