This is a really wriggly tin of worms, Nick and myself...and one or two others here...are commercial builders so we view things rather differently.
Cheap kits are cheap for a reason and all will have a heavy cost in man hours to build, for the commercial builder that equates to a hefty bill, eye watering in some cases. For the hobby builder it's pure man hours and for many that is an aspect they enjoy and quite frankly, probably relish so fair play to them. For myself, I'd rather save those hours and go down the pub with my mates or take the wife out for a meal.
Cheap kits often require replacement parts and there in lies another wriggly tin of worms, what is (commercial prospective) the most efficient way to achieve that, both Nick and I have colluded on supplementary etches, 3D parts and scratch building. Things like boilers, fireboxes, cab roofs, side tanks are perfect for scratch building, there's little to be gained from having large slab objects etched, more so at today's prices.
Regarding the Merchant Navy, essentially we were looking at what amounts to nearly a full kit, that's very expensive in etch production and the roof is a nightmare, I'm just now going through that with my two BLP builds. Whilst I am absolutely confident Nick could have formed the panels we both decided the time taken to do so would have placed the project out of the clients remit.
For this very same reason, there will only ever be two EM2, the effort required and the budget needed to finance all the etches, 3D and after market parts (pantographs, bogies etc) simply makes it unattractive cost wise. On top of that and despite all those aids to building, there is a huge amount of scratch building Nick did behind the scenes to join all the bigger pieces together, that aspect is often forgotten and overlooked by the distraction of the etches and 3D.
In short, if you have plenty of building experience you'll probably eventually get it done, but have a large bin at the side of you for "left overs". Unfortunately the original Merchant Navy would not be an easy candidate for scratch building unless you have the skills of Mickoo.
Thanks Brian, but I would not consider my skill set to be at a level where scratch building one of these was practical, some etches and some 3D, then maybe; but cutting metal, nah I leave that to the professionals like Nick, that's his expertise as is mine in CAD and 3D.
I have to say fair play to Nick on this build, etches would have helped in some cases (but not many) so to hand ball all this is quite an achievement. It's not something I would have taken on I have to say; it's several levels on from the 3F and Garratt.