A lot of reasonable, balanced, critical comments already so I'll just add a couple and provide my background for feedback.
1. This price increase notification should be emailed to all users not just posted in the forum. I checked my last two e-bills and there is nothing noted there, so if I hadn't seen this post I assume my first notification would have been an increased bill on my credit card? Not the best way to maintain your customer relationships IMO. Ironically the only reason I have been visiting the forum recently was to see if there was any news on more attractive options to my current Sonic service than those currently available.
2. Its your business to run as you see fit but IMO bumping the charges on the Fusion services, presumably affecting a substantial proportion of the 90% of your customer base not already on fiber and thus a quick way to increase margins for future investment, is also just as likely to prompt many to consider alternatives, especially when there is no indication on fiber rollout. Living where I do in San Jose I was unlikely to see even Google fiber service for another 2-3 years (if they had held to their planned schedule), so asking me to subsidize Sonic fiber for presumably at least as many years or more, assuming it ever gets here, is several bridges too far.
In my case I was already considering options for reasons that will become obvious, like others have mentioned bundled voice with its attendant taxes have no value for me at this point. I currently "enjoy" Fusion x1 at sub-4mbps download due to CO distance and at ~$57/mnth inc taxes which will now increase to ~$67/mnth. Clearly Fusion x2 is not attractive at this download speed. My only available option for a reasonable increase in speed versus cost from Sonic is Fusion FTTN x2 which will now be ~$96/mnth inc taxes with the new increase; it wasn't looking attractive at $86/mnth. For my needs just about any internet-only service option from the competition (Comcast, AT&T, DSLExtreme) is looking more attractive at this point. Its looking like Comcast 25mbps may be the best option, dependent on the install costs, versus DSLExtreme.
I wish Sonic the best for the future and if you ever make it with fiber to my neck of the woods I would likely be back. I have stayed with Sonic (probably too long for my own good) for the attributes that you outline but these aren't worth a potential $30-$40 per month premium (after the first year terms expire from competitors) for a service that is actually broadband.