For a firm that has at times appeared near-paralysed by indecision, division and lack of leadership, Herbert Smith is certainly making an emphatic statement with its full financial merger with Freehills. True, the firm procrastinated in Europe to the point where belated attempts to make ground ended in public reversal.

But in this case, Herbert Smith has proved sceptics wrong by actually getting the deal over the line. By the same token, it wins praise for abandoning the customary international merger fudge to go for financial integration – albeit with different comp systems initially.

There are other factors to commend a deal which, in truth, seems a little hard to fathom at first glance, but looks more convincing on closer inspection. The practice fit is logical and complementary, with the two firms sharing a focus on high-end litigation and corporate, and a common industry focus on the energy sector. If anything, Freehills has the stronger reputation of the two, hitching Herbert Smith to a leanly run, top-tier practice apparently on an upward track.

The deal also creates a genuine giant in Asia, where Herbert Smith already has a sizeable practice. It does nothing to fix the gaping holes elsewhere in the world, but does deliver very substantial additional investing power to fix the problem via the creation of a global top 20 practice with revenues of about £800m.

That's a major plus – a fundamental problem facing Herbert Smith is the need for serious investment in markets such as Germany and the US. Also in the plus column is profitability, which is closer to comparability than most people have allowed.

That is largely where the good news ends, as the deal brings inherent risks. For one, there is a sizeable currency risk and an army of Australian lawyers whose success is tied to the Asia-driven commodities boom at a time when the region's main economies are cooling. And sheer geographic spread and scale will present significant logistical challenges post-merger.

There's an awful lot riding on an untested formula. Even if the business case works, Herbert Smith has little experience of such mergers and lacks the proven central management typically required for such tasks. City institution meets Australian leader may be a winning proposition, but has Herbert Smith got the managerial chops to pull it off?

Potentially as problematic are indications that a somewhat factional partnership may not be 100% on board. Are such problems insurmountable? Certainly not. The tie-up presents Herbert Smith with a fantastic opportunity to rethink its business for a fast-changing world and industry. But it's going to take an awful lot more leadership than has previously been displayed to get there.