I rode the length of the Lioness today.
Naming the lines reduces the difference between the tube and overground trains - emphasising the integrated nature of the network. If you want to name them, they areas good a set of names as any.
I agree - it was ridiculous having 6 different overground lines all just known as the "Overground" with no difference in names - made it far harder to navigate, especially as you *did* have interchanges between them. Giving them all names and colours will make it easier to navigate and make it feel less like the "poorer cousin" to the main underground lines (especially as the majority of the lines/stops on the overground appear to go through poorer/more run-down areas).
I have absolutely no issues with the names chosen - especially as the Underground lines have a lot of Royalist/Right Wing names (Victoria, Jubilee, Elizabeth Line, etc) - in fact, the fact it is triggering the Right Wing Gammons is reason to support it (you only have to go on the youtube comments for TalkTV, GBNews and the likes to witness some horrific). Claiming things like "It was done as a deliberate racist insult to the English.", "I’m outraged by this, how dare that dictator try to rework British history", "Why can't the prime minister or government just sack Khan......disgusting , I'm surprised there's not a Palestine line".
Also, I just put myself through the nearly 7 mins GBNews YT video on that matter - it seems like their main issue is naming one line the "Suffragette" instead of "Suffragists" (because in whomever the guy is words, "the suffragettes were violentm they bombed things, they smashed things") which is laughably silly - ignoring that nowadays we tend to (as his co-anchor mentioned) bandy the two together under one branch (he even mentioned his outrage of having Millicent Fawcett being used to advertise it).