When it comes to immigration, there's two different concerns that we shouldn't try to conflate. There's the security aspect and the work permitting aspect and they should be handled almost entirely separately. As far as security goes, I'm fine with DHS and the various three-letter agencies being able to weigh in and veto someone's visa based on whatever vetting process they need to put in place. This part of the system doesn't seem particularly broken, despite how much Trump wants it to be broken so he can keep beating that drum.
As far as the work permitting process goes, that part is almost certainly broken. The H1-B system benefits body shops the most and is almost impossible for smaller businesses to use. It should be scrapped in favor of a system that puts the onus of determining who gets a work visa on the employers rather than the government. A points system is an unnecessary proxy for actually determining someone's ability to do the job and the job interview process is, despite how imperfect it is, the best tool we have for making that determination.
I'd be in favor of allowing any US company to get work a permit for any employee they want to hire, provided they pass the security screening. The necessary caveat would be that the company would need to maintain a certain ratio of US to immigrant employees and salary. This would destroy the body shops that know how to game the current lottery system. And it would make hiring immigrants much more predictable for smaller companies that currently don't benefit, at all, from the immigrant labor pool due to the complexities involved in sponsoring an H1-B visa. It would take race and country of origin almost completely out of the equation, at least from public policy since those decisions would be made by employers. And it would make life better for H1-B visa holders as well, since they could easily transfer to any company that was below the required ratio. Other countries have a ratio system and the worst that happens is they game the system by employing locals in no-show jobs, which doesn't seem like such a bad deal for those locals. It seems appropriately protectionist while still making it as easy and predictable as possible for immigrants.
As far as the wall goes, it's the dumbest public policy suggestion I've heard in my lifetime. Speaking as a Californian, our economy won't work without the steady stream of near-slave labor that comes across our southern border. It's an uncomfortable truth, but almost everyone in the state depends on the work of these people, whether they realize it or not. The fear of deportation keeps them from using services that cost us money. Getting rid of them would be like getting rid of the motor oil in a car engine. All the individual parts would still be there, but the engine would break down. And on top of destroying our economy, the wall would cost at least $20b as well, and Mexico won't be picking up that bill.