Difficult? Yeah.
Extremely difficult? Some parts.

Doable? It's been done. It's being done. This game is hard, hardest I've experienced, but it's completely doable. I think with this game teams had to cut down on their priorities and focus on doing a select few things really well instead of everything. As stated in one of the many 1114 white paper resources that I've read 1000 times, "If I had 30 unites of robot, I'd rather have 3 units of 10 rather than 6 unites of 5". While some very good teams in previous years could do everything and more with 10 units of robot, I think due to this year's challenges even all-star teams are cutting back on doing everything and focusing on being able to do a few things really well.

That being said, I still know a lot of people who are trying to do everything imaginable, and may succeed at it. Maybe you'll figure something out before the build season is over and make a kick-butt do everything robot. But on the off-chance you don't have an epiphany anytime soon, I think it would be a good idea to start focusing in on a few major priorities for your strategy, and once those are done look into making them better, and MAYBE after that look into adding those things you couldn't fit into the build season.

There are 3 weeks left. You're not alone. Most teams are behind schedule this year, ourselves included (we'll be cutting steel tomorrow for the first time). Make the best out of the time you have left, and make sure what you get at the end of it does whatever it does at 110% power.