Say Tannehill does start from day one, or even a little later but gets a significant amount of starts... you don't think that having as good of a WR core, no matter the age, will help with his confidence? Can you imagine him starting with five Edmund Gates' at WR? Ocho may not be a long term piece, but to say it's clearly not going to help in the future is a little narrow-sighted.
Steve Smith of the Panthers had an awful 2010 campaign with 500+ yards and 2 TDs. 2011 he blew up and was his QB's go to guy from day 1 an an offense that's pretty anemic when it comes to offensive weapons. The QB went on to throw for 4000+ yards, break rookie records and earn a bunch of post season rookie rewards. Tell me he would have done all of that if his #1 WR was Brandon LaFell.
You want to go to younger guys who have potential. We have relatively young receivers still. That's all we had until Ocho came. And we're talking WRs that have had years on the roster to improve. We've hung on to Wallace and Moore long enough. If they can't make marked improvements that are obvious during training camp, and Ocho proves he can be a consistent contributor, then I'll gladly cut one of them for Chad.