You can say these are "myths" but that doesn't make them true.

Your api doesn't work with other network switch and firewall vendors.

Using channel partners is a complete crap, off course they support you they buy your stuff. Talk to end customers. Get them to put their names to standing behind your SDN over other SDN vendors.

White boxes are cheaper and easier to deploy than cisco gear. You can get people to stand up an equivalent compute cloud to a cisco vblock at 1/10 the cost of standing it up.