Broker-dealers and hybrid RIAs should have already anticipated the impact of the rule, argued Chris Hamm, senior vice president at Independent Financial Partners, a hybrid RIA in Tampa, Fla.

“If you’re an RIA, you’re already well-prepared, or you should be,” Hamm said.

Hamm said that over the past few years, the percentage of his business's revenues derived from fees has gone from 40 percent to 65 percent.  

"The rule should push us further to the fee-based side,” he said.

At the Fidato Group, an RIA in Strongsville, Ohio, CEO Tony D’Amico wonders how the rule will impact advisors managing both qualified retirement accounts and brokerage accounts, and hybrids who offer insurance and annuity products as part of a comprehensive wealth management plan for retirement investors.

"It still isn't clear how this will work for someone who wants to be a fiduciary in one capacity, but who isn't going to be a fiduciary for a client's trust account or individually-owned account," D'Amico says. "What if they want a fiduciary for their comprehensive retirement plan, which not only includes investments but estate planning and insurance? There are good brokers out there with good intentions – but they are not required to put their client’s best interests first."

Dave Edwards, president of Heron Financial Group, an RIA in New York, thinks the rule will benefit RIAs and consumers initially, but could radically alter the RIA industry over the long term.

“I expect that a lot of hungry broker-dealers will shove themselves into the RIA space and rebrand themselves as RIAs,” Edwards said. “That will continue the process of fee compression."

He expects the pressure on fees created by the new rule, as well as continuing demands for better technology, will drive a lot of small practices out of business.

"I think that only firms with more than $1 billion in assets will be viable," he said. "There will be a lot of consolidation over the next five years.”