In my opinion, the challenge (at least for a conservative investor like myself) is wading through the "junk" to find the few pearls: high quality sponsors and deals.But before jumping into deals and sponsors, I would recommend taking a step back.

For me it's continuing to develop a new partnership with a self storage deal sponsor I'm investing with.

They are easy to get into and if the sponsor is good it’s a great way to get really good returns. 

Life and Disability. outside of employer provided benefits.Next, max out on employer sponsored retirement plans

When it comes to investing ones equity nest egg or retirement savings people often want to be able to look the sponsor in the eyes, have a conversation and get their read.

@Gamaliel M. regarding syndication asset classes: One of the upsides of investing passively is you can diversify by asset a lot more easily than sponsors can.

I need help finding a broker who will sponsor me.

In any case, if it is a fractionalized investment (a number of silent partners) it is probably done through an LLC, and the sponsor will produce a K-1 as pass through income, and will detail what kinds of returns and deductions are in that report.To fully understand this you should ask the sponsor and consult your CPA for the implications in your particular tax situation.

After all, if the Sponsor is saying it’s a great deal, that should be enough, no?

As @Maxwell Manatt points out- does everyone know their role and what is expected from them - because unperformed duties do not raise someone to the level of a sponsor/issuer and may create the presumption that the specific person is indeed an investor who actually purchased a security.