When Ireland allowed same sex marriage, all civil partnerships could be converted into marriage, and no new civil partnerships were allowed- a recognition that civil partnerships, like in the U.K., were simply a very slightly watered down alternative to marriage by another name to get over our discomfort around letting gay people marry.
In other European countries, civil partnerships usually are something less than marriage- the kind of first stage protection you might want if you live with someone but don't yet have kids/want the full legal responsibilities of marriage.
Ireland actually has automatic cohabitation laws which are new, but sensible- nothing like the protection of marriage but essentially if you live together for 5 years without children or two years with children, and you split, a court can get involved and order a degree of maintenance, property reallocation, etc. It's opt-out rather than opt-in.
What people are arguing for here seems pointless to me- it's just marriage by a slightly different name. Where there's a gap is in the in-between stage, as they have in other jurisdictions. My marriage didn't have flowery language, or god, or any patriarchy. I prefer to reclaim it as an equal partnership than in any way accept lesser rights or protection.
But yes- I think the UK civil partnerships as they stand should be phased out, and potentially a new interim level of protection introduced for all, however I think this variant of civil partnerships was always a fairly pointless cop out and instead of coming from a history of patriarchy it has a history of homophobia instead (the reason for the adultery rule not being included is because gay sex isn't proper sec) so I'm not sure why that's any better.