"With a fast and furious first strike following a coordinated special forces sabotage campaign? I don't think anyone could help Taiwan in that case."
You alluded to why this could not happen. The Chinese could possibly pull off a Special ops strategy but they could never follow it up with the big hit...why, because they would tip off Taiwanese and US intel mechanisms when they start to board the ships, group the transports etc etc.
"recent sub improvements shows that they're at least beginning to look forward to developing worldwide force projection capabilities."
It will take them alot of time and resources to do this...even at the current rate, in 10 years they MAY be able to send some battle groups thourout Asia,,,a regional projection that may get Singapore and Indonesia concerned but nothing that the Japanese or the US would really fear.
"The real question of it would be whether China has the capability to get enough boots on Japanese soil"
They do not have the ability to do it...Japan would crush them if they attempted an amphib on Japan....the entrance of the US (do you really think we would permit this?) would actually be a quick death for the Chinese forces, as opposed to the slow death the Japanese would give them.
"While they can aptly defend themselves, anyone adopting a siege mentality..."
They would aptyl crush the Chinese. As far as strategy and defense only, look for the Japanese to get over their SDF philosophy in the next 20 years as China becomes stronger.
"You can only suppress so much with air power"
In defense of an island, we could stand back and use our superior navy and airpower indefinately, but it wouldn't take that long....The Taiwanese and the US would turn the Taiwan Strait into the Marianas turkey shoot II. China's 30 ships that are first line type craft would likely all be sunk within 2 weeks.
I don't see us sending any troops there...maybe in the special ops scenario we'd pour some quick troops in...but that island is going to be saturated with alot of BMs and it wouldn't be a fun island to be on...when it was all over Taiwan would be devestated but holding the island, China's airforce and navy would be humiliated and they would loose troops by the 20s of thousands...what is more China would have shown its true face and be shown to be the rogue that it is.
I think we're going to have to agree to disagree on China's current military capabilities. I do, however, think we agree that it'd be a good thing if neither of us is ever proven right or wrong on this issue. Here's to hoping that China, like all our big enemies, keeps a cool head.