Yes. Price is the key because it determines risk, but more on that in a bit.
Brandon Marshall would be the most dangerous receiver Seattle has had since Joey Galloway.
Football-wise, the Seahawks' offense would change dramatically overnight with such a dominant physical presence at receiver. Marshall's presence on the outside would allow T.J. Houshmandzadeh to play more from the slot, lowering the cost for the offense if John Carlson or any other tight end spent time helping in pass protection.
The Seahawks haven't had a truly dynamic receiving threat on the outside since parting with Joey Galloway (Koren Robinson had the potential, but never developed). Marshall offers much more than Galloway ever did.
Back to the risk part.
I'm somewhat sympathetic to the thinking that Marshall's off-field incidents -- including charges relating to domestic violence -- should disqualify him from consideration by any self-respecting franchise. But it's also important to differentiate football character from personal character. The Seahawks arguably haven't done that well enough in recent years. They've gotten a little soft and lost their edge.
Landing Marshall for a price low enough to justify the risk wouldn't automatically turn the Seahawks into a rogue organization. The team could always discipline Marshall or even release him if his antics became too much of a problem.
An organization with strong, unified leadership should be able to handle a mercurial personality or two -- particularly when there's so much to be gained on the field.