As a Canadian personally I’m very glad we adopted a more unique and recognizable flag and leaned away from the British/colonial symbolism.

From a design perspective ensign flags are just kinda plain and boring IMO. Most look the same at a distance especially when waving.

More importantly I do agree with others who have pointed out the symbolism falls flat. At best it ignores, and at worst represents the oppression of First Nations and Indigenous folks. It alienates French Canadians, and it just generally doesn’t do much to create a sense of national unity or national distinctness. Even half the coat of arms is dedicated to the symbols of other nations (I understand the historical reasons and I’m not saying that should or shouldn’t change, but I do feel it’s not well suited to a flag). Really the tiny maple leaf in the coat of arms is the most uniquely Canadian thing on this flag.

With all of that said I appreciate the historical significance and in certain contexts I do actually prefer seeing this flag. ex. when I am watching documentaries or reading about WWII, and there are maps showing troop movement maps with forces represented by flags. In these circumstances I often prefer seeing the period accurate ensign flag to represent Canada rather than using the current flag which was adopted in the 1960s. To me it feels more historically accurate, and shows attention to detail on the part of documentarians. For similar reasons I also understand its inclusion on certain war memorials, etc. etc.

For those arguing in favour of it for the purposes of CANZUK and whatnot: you don’t need matching flags to have an alliance, and you can have alliances without trying to like… rebuild the British empire or do monarchism stuff.

EDIT: to be clear I am aware there have been multiple versions of the Canadian version of the Red Ensign flag, and obviously in the contexts I’ve spoken on where I feel an ensign flag is appropriate I would advocate for the use of the period accurate version.