I get it, but getting client feedback early in the planning process promotes optimal feature targeting directly tied to established client value. Otherwise you're operating in the silo of your company's opinion only, which IMO could cause you to fall short on meeting some requirements your clients actually have/need/want. Iterations are on compounding enhancements with minimizing tech debt incurred, however if you pattern a solution that couples you to your vision (without consideration of the clients'), shifting to meet additional/different requirements may prove difficult (or simply costly that could have otherwise been avoided). Just my .02, been through it in a different industry a number of times.