Well the jump bridges allowed access to people from another alliances, the difference is in the fact that the new structures allows different alliances to link their jump gates to each other. Currently to do that you had to have the IHUB in the same alliance for the jump bridge which is what most alliances did. So there is little real change here.
No real change…, you end up near a structure, before you ended up near an armed POS, the POS had automatic shoot capability the structures do not.
Jump Fatigue is in a good place at the moment, I think it is correctly balanced. When it was first said that there would be no jump fatigue, I was happy and continue to be happy because the number of times I had to miss out on sub caps roams because we had fleets later involving caps was truly annoying. So that will increase content a bit.
The Capital ships using them is a change and that they have no jump fatigue is also a change, it increases power projection, and diminishes the jump fatigue in terms of power projection, however do you realise how debilitating that jump fatigue really is and how limited the range is even now?
And then you have to look at what the defender can do against this type of use, they know where they will jump too, so they can water board them which is bubble them continuously to slow them up. It is very effective indeed. It also makes it easier to hunt and kill capitals that use them. So all in all I think it is fine and will want to see how it develops. I noted the anchoring and the timers on them and I think CCP did a very good job on working it out. Arrendis did a very good post on this in the CSM thread which I will link for you to read.