Firstly, as far as I'm aware, the closest the proposed Crossrail 2 route gets to "South East London" is London Victoria, the route south of the river following a very south western path.
Secondly, of those projects you mention only DLR affects "South East London", and then only a very tiny bit of it. Let's not forget your seemingly much ignored NW London has benefited from first the Metropolitan Line and then later many other tube lines, with the far more frequent services that go with them. South East London on the otherhand has little such provision, with the development of the Overground south of the river being the small glimmer of hope that perhaps TFL wouldnt be better described as Transport For North London.
Gipsy Hill station, which serves my old stomping ground, sees a far worse level of service provision than the likes of Harlesden and Willesden Junction, yet as far as I'm aware there is little to nothing being proposed to improve service to it and other similar stations in SE London. Not all SE London stations are East Croydon!
My bad ,got the route wrong
I was referring not just to tube services , but the significant amount of money East London has received for the projects stated earlier , to allow regeneration . Look at the 02 arena , the Emirates cable car for further examples of how those areas of SE London has had money thrown at it
In those terms , areas in NW London have received comparatively less . For example, I am not aware of any such investments where I live , near Moor Park , or in Harrow
I don't venture out to East London much , but isn't there the Jubilee , Central , District and Hammersmith and City, DLR , National Rail and Overground . That doesnt seem too bad