Basically now 'the business' A330 is Virgin's business class offering. The other 2 seats together on 737 is premium economy and they have no right to call it business. Then there is economy and economy Xtra legroom which are correctly named. So 4 classes , except they try to pass their premium economy off as business.
As someone else mentioned, the VA 737 J product is pretty much on a par with the QF equivalent. Furthermore, both the VA and QF 737 J products are far superior to any domestic J (or domestic First in the US, or even short haul international J within Europe) that I have experienced with any other airline. I have a reasonable bit of experience in that regard - BA, LH, AF, LO, WX, DL, AA, UA, VX, AC, and probably others that I can't think of right now. I even once got stuck on an overnight flight with SQ from SIN to MEL in a J seat that was essentially the same as the QF 737 J seat due to an aircraft substitution, when I had booked their (at the time) class leading A380.
By all means complain about substitution of an A330 with a 737 without proper notice or compensation, but your argument that VA's 737 J product should not be called "Business" doesn't stand up to any sort of scrutiny when you compare it against equivalent products offered by other airlines. The fact is, every airline that I have flown with has a range of different seats/service levels within their Business Class offering. If you feel strongly that every variation within an airline's fleet/service level should be described as a different class of service, then fair enough, but VA is a very strange target to pick with this complaint, considering their J at least offers a significantly better hard and soft product to Y in all cases, which is not true of many other airlines.
I'm not at all surprised by your experience nor the nonsensical response you got from VA. That is entirely typical of my VA experience overall and the way they handle things.
In my opinion, VA made a massive mistake by not putting a decent J product on their major fleet (737). There are proper shell style business seats for single aisle aircraft, they should have gone for these, installed them on the entire fleet (including the 330s) made their J consistent and only upgraded the 330 to an international standard business product when they finally launched international services on the 330.....7 years later. Why they were even running dual aisle aircraft for the past 7yrs is a bit of a mystery. Yes, yes everyone hates single aisle aircraft for long flights, but both VA and QF use 737s on those flights anyway. Would have been better off to just put a decent J seat on the 737 and made the experience tolerable on a single aisle aircraft.
You want shell style J seats on their entire fleet? Seriously? VA's fleet mostly serves daytime flights that are 1-2 hours long. The Coast to Coast flights are an anomaly in domestic routes in Australia, so kitting out the entire fleet to cater for those routes would make no sense. To be honest, as awesome as the A330 J product is, I think it's unnecessary even on MEL-PER flights, except the redeyes - it's not as if you can (or necessarily want to) have a proper sleep on a 3.5-4 hour daytime flight. I agree the inconsistency has created a problem, but more because of the constant aircraft changes and how they handle them. They should have either (a) stuck to advertising the basic 737 J product, and treated getting an A330 as a bonus or (b) brought in a difference in pricing between the two products and then did their utmost to stick with the aircraft that people booked on, or provided compensation in the event of a change.
BTW - I agree with you about Economy X - I would be very surprised if many "average punters" would consider paying an extra $58 per person per round trip for this. Most people place far more importance on price than on comfort - hence the massive success of (literally) no frills airlines in the US and EU.
