I've been looking at these 3 ideas for the past few days... quick thoughts...
1. The MSI+KKG Broad Street plan is what was laid out for the 2010 Downtown Strategic Plan, which was adopted, so we can assume that's moving forward in some manner within the next eight-ish years:
http://www.columbusunderground.com/forums/topic/downtown-2010-plan-idea-4-broad-street
2. The Pizzuti Companies "Scioto Peninsula" is somewhat similar to what was laid out by the 2010 Downtown Strategic Plan, although with a slightly rearranged placement for the types of properties and a lack of towers:
http://www.columbusunderground.com/forums/topic/downtown-2010-plan-idea-11-scioto-peninsula-development
3. The Big Moody+Nolan skyscraper idea seems to be out of left field. I like that they're trying to re-imagine the way that corporate recruiting might occur Downtown rather than in the burbs, but I have to wonder if a 1000-foot 60-story tower makes any sense at all.
Any relocated company is going to first and foremost be looking at location expenses, and a monolithic tower like this is going to cost maybe around a billion (with a B) just to get up and running. When compared to a "corporate campus" style suburban development, the cost ratio is bound to be much much higher.
Meanwhile, if the purpose is to fill in the underutilized spaces Downtown, this type of development only conquers a single block. Sure, there's bound to be more development that follows, but if part of the goal is to fill in "holes in the city' why are they spending so much money at filling the sky rather than the holes on the ground? I imagine this building might house a few ground-floor retail amenities for office workers, but how many can you fit in one building?
Instead, we've got a global company like Nationwide, who has invested roughly $1 billion (with a B) on building an entire neighborhood of buildings in the Arena District. It's mixed-use, it's full of amenities in multiple buildings, and it's done more to conquer acres and acres of underutilized land in a way that no single skyscraper can.
Modern skyscrapers look great on postcards and promotional photos of our Downtown, but I'd much rather see another Arena District (or two) before seeing a big glass monument to the clouds.
My 2 cents anyway...