Who knows. I thought Muir outplayed Merling. Both Muir and Hargrove brought a passion to the field that led me to think they would make the team. I thought that was one of the things missing. A loud motivation guy on the defense.
If you're Mike Singletary or Ray Lewis (notable yellers of past and present), you'll get the attention of rookies and vets alike. You better be a d*mn good player if you're going to make a habit of it.
If you're a marginal player on the bubble, you might perk up the rookies ears and get them jazzed, but it won't take long before the vets will want to say, "shut the F up and just play". Constant yelling without the performance to back it up has a short shelf life...in due time it becomes distracting and obnoxious.
The yelling issue aside, in case you don't find it compelling, the trend in 3-4 is for lighter, taller more athletic DEs in the 285 - 305 lb. range who can rush outside in base or inside in nickle. SF and HOU have demonstrated how it might work. If you're going to head in that direction, you've only got room for two sumo wrestlers...in our case Raji and Pickett. There really wasn't room for Muir. He was likely injury insurance for Raji and Pickett.
Merling is the 6'4", 295 lb. 3-4 DE with some athleticism...the new prototype. TT said as much. Muir might be the better football player but was redundant; Merling has the better potential at a position with more question mark. In short, we're looking for the next potential Cullen Jenkins wherever we can find him among the numbers. Merling doesn't have much time to make his case, however.