It is quite common for law suits seeking similar relief to be consolidated.
In this instance, neither is a big deal. The condo owners have no case, --taking Samuels word that these condo owners are simply re-hashing arguments that they've made previously on numerous occasions. Their arguments were heard and rejected. There is no legal right to a viewshed; if one wants to preserve a viewshed, purchase an easement protecting such from all properties that control the view. Light/shadow, noise are often regulated, through zoning, codes, or regulation. And his project was approved after review of its environmental effects.
One doesn't keep getting more bites of the apple. Anyone who wants to spend (waste) their money can find a lawyer to take their case.
The Hotel Eliot has a case, but it is easily resolved.
As to litigation, I participated in a very recent case in DC, brought by the Preservation League which sued the District for approving a demolition permit for a historic industrial building. (I was in opposition to the Preservation League, which lost badly.)
The developer was not sued directly, but was allowed -- as they owned and were re-developing the property -- to enter the case as an intervenor. Taxpayers paid for the District's lawyers; the developer's lawyers fees for just this case were undoubtedly in the medium-high six figures.