Not quite. You arent just block shifting one time like "all accs now have +20 str". You are also shifting the progression of each ilvl to have more impact. Instead of Crafted pieces are only the best because the str stat goes up by miniscule amounts that the overload of secondary pentamelded stats can overcome. Rebalancing the str between left and right means the right side actually gains significant amounts of str so the extra 4 melds on crafted gear are outstripped by the raw str gain. Same as happens with DPS, just by a slightly lessened degree because the overall str of tank gear is still lower than DPS. That is just the bare bones 'simplist' solution because it is just a raw stat shuffle of existing stats and therefore impossible to F up and takes miniscule dev time. For comparison, including weapon, about 30% of the damage stat for DPS jobs gear is in their 5 accs. For tanks to reach that split accessories would need to have 64 str on 350 gear and 73 on 360 gear and so on. This is linear ilvl progression. The downside of this one is weakening our left side gear, but the upside is it leaves the relative values of everything else the same. Secondary stats, overall damage, etc will be entirely unchanged with this method. Not sure how you gather this will make crafted gear somehow more required. Weakening left side gear isnt really a 'bad' thing because right now it is the ONLY side that matters and thats a problem. It doesnt really matter how you view it. Left side matters to much, right side matters to little. Its just a different way of saying the same thing. Its uneven. This fixes that.
That said, I slightly prefer my second suggestion of flatly giving the same str on tank acc as DPS at all ilvls and lowering weapon damage by a flat % accross the board to counter the damage inflation. This would give us identical % damage progression in every respect to DPS via gear, though is slightly more work to implement (It is still just gear number changes, but requires some basic algebra to do properly, but that shouldnt be to much to ask), but retain the overall lower tank damage that we currently have and will continue to scale below actual DPS jobs.