That means for many credit unions job one remains launching a mobile app and also offering what is emerging as a must have, and that is mobile remote deposit capture.

Beyond that, Resendiz said that at Digital Insight a big current push is to decouple mobile banking from online – in most deployments mobile is parasitic on online and cannot stand alone.

But, lately, said Resendiz a clear trend is the growing number of mobile-first consumers – "they may sign up with online banking but they never return to that channel" – and so Digital Insight plans to roll out a mobile-only solution "by this autumn," said Resendiz.

Most experts expect that push for a mobile-first strategy to percolate into many financial institutions this year and the reality is that it may be a big change, but it is not likely to be one that many consumers notice because it happens under the hood, out of plain view.

Another reality: Experts said that credit unions have to continually upgrade their apps, to stay competitive as consumers clamor for more functionality in all of their smartphone apps. Elaborated mobile banking expert David Eads, "Many credit unions have 15% of members using mobile now and they think that is good enough. It isn't. Many big banks now are at 37% and climbing. Credit unions, to remain competitive, need to be approaching 50% usage this year," meaning that one of every two members will have a mobile relationship with the institution.

That means credit unions have to work hard to increase the appeal and usability of their apps.

Yet a kind of simplicity is baked into every mobile banking app by virtue of the fact of the small screen, said Gary Ambrosino, a mobile apps expert and president at TimeTrade, which sells scheduling software to many financial institutions. "There's a limit to how complex a task can be on a small screen. It's too easy to lose users. That's a hold up when it comes to introducing new features on the mobile device."

In other words, it is easy to look at online banking sites on a 30-inch monitor and wish that all those features were accessible via mobile – but for now the constrained reality is smaller and that's not likely to change soon.

So, what are leading edge credit unions cooking up now? Know that many credit unions in fact plan to roll out key, new features this year. The tools credit union executives presently talk about adding will not be dramatic – there is no mobile remote deposit capture "must have' feature in the list – but they will, hope these executives, up convenience and utility of the mobile app. Out of that may also come more users.

A case in point: Navy Federal is introducing a capability it calls "PIN and In," said Gound, who explained that logins via the mobile banking app now can be done just by entering a four- digit PIN, which is much easier than typing long passwords on a glass screen. "We believe it is very secure and also very convenient for members," said Gound.

That may seem small but if it results in more member engagement, that payoff is real, Gound said.

She added that at Navy Federal many new capabilities are under review, including offering credit card and auto loan applications via mobile and the institution is "looking at biometric authentication" such as fingerprints. But it is not ready to roll out such innovations, not yet.

At $5 billion Digital Credit Union in Marlborough, Mass., vice president for support services Julie Moran said that the institution plans, soon, to roll out a feature for members that will let them swipe within the credit union app to see their account balances. "You won't have to log in," said Moran.

That puts DCU alongside Randolph-Brooks Federal Credit Union, a $5.6 billion Live Oak, Texas-based institution which last fall released a widget that lets members who opt in see a self-refreshing balance with no login required.

The $4.1 billion Pennsylvania State Employees Credit Union in Harrisburg, Pa., makes three, said Christopher Owens, mobile product manager, who added that "we will release a widget this year that will let members see their balances. It's very convenient and we know members will like it."

Also in the works at PSECU is a new person-to-person payment service, powered by PayPal, that will let any PSECU member send funds to a third party who does not need to be a PSECU member. However, they need to be a PayPal member, according to Owens.

He indicated that PSECU had been looking for a way to offer P2P for some time and, between the ease of use of the PayPal tools and that company's sizable brand recognition, PSECU decided to go with them.

Another PayPal plus, Owens said, "The money transfer is essentially real time. You can be at a swap meet, agree on a price with a seller, and send over $20 in real time to complete the purchase. Our members had told us they wanted this kind of capability."

All these changes sound tiny? But they will add utility for members and that, said the experts, is what mobile banking app development presently is about: Introducing small features that add incremental benefits that members can enjoy immediately, with little or no learning curve.