While I'm inclined to broadly agree with you about unification, I'll take exception with the comparison to the IDF, which I feel is irrelevant to the Canadian context. The IDF enjoys continuous and generally growing budgetary and political support. In Canada, the forces are almost continuously in budgetary straitened circumstances, emerging briefly (as we did in the mid-80s and late 2000s) every generation or two. In that context, strong service identity allows minority services to maintain important capabilities in the face of the "tyranny of the majority".
Consider a naval CDS in a "strong centre" organization. Budget cuts come down and where do they land? Because he has limited to no exposure to, say, the patrol pathfinder capability, he doesn't appreciate its cost-benefit and it's put on the chopping block because there's no strong service to mount a reasoned defence of it. Now consider the much more likely scenario of an infantry or armoured CDS and pretty much every naval capability beyond troop transport and shore bombardment and you'll understand why the RCN and RCAF tend to favour a service-oriented structure.
What we often refer to as "service parochialism" is really just a natural human bias in favour of what we understand over what we don't. The sum of all military capabilities really is too much for one man to know thoroughly. Except in the unique context of the IDF's stable-and-growing budget, in the absence of service-level control crucial capabilities end up getting dropped because of inherently biased decision-making.
Again - I'm not arguing strongly against unification (especially as it has recently evolved), but I do think a strong service culture protects commanders from their unknown unknowns.