The Samsung "relationship" can be ended very simply by Samsung selling its shares. They will not be interested in screwing up their own business to aid Seagate.
Next thing, customers don't like the effects of the extreme consolidation in the HDD market one bit, with its inherent price fixing (500GB drives today are more expensive than they were 7 years ago, never returned to pre-flood levels).
Adding Seagate's sleazy business practices, their heaps of clattering, unreliable drives, I think you will find few customers who want them to become dominant in SSDs.
Its similar to Microsoft: customers instinctively don't want them to extend their monopoly to tablets and phones, so they stay away from the product, inspite of the massive evangelizing Microsoft has paid for.
The only thing welcome will be additional pricing pressure to the overall market. If Seagate forces down prices a bit, people will happily buy more Micron, Intel and Samsung drives. OEMs will be a vector for Seagate though, since most spec sheets fail to list the brand of SSD used, you might end up with one without knowing it.