The WAP4410N replaced the WAP4400N a while ago. So if at all we will only see an update for the WAP4410N.
However all of what Draft-N does is also in the Standard.
Standard devices and draft-n devices can interoperate.
Basically we would need just to re-certify the existing accesspoints according to a new test suite.
No firmware upgrade required.
For any 'real' improvements to an Accesspoint one would need newer hardware which allows more datastreams, more antennas etc., bigger CPU to allow more throughput
here from wikipedia
"As of mid-2007, the Wi-Fi Alliance has started certifying products based on IEEE 802.11n draft 2.0.[10][11] This certification program established a set of features and a level of interoperability across vendors supporting those features, thus providing one definition of 'draft n'. The Baseline certification covers both 20 MHz and 40 MHz wide channels, and up to two spatial streams, for maximum throughputs of 144.4 Mbit/s for 20 MHz and 300 Mbit/s for 40 MHz (with Short Guard interval). A number of vendors in both the consumer and enterprise spaces have built products that have achieved this certification.[12] The Wi-Fi Alliance certification program subsumed the previous industry consortium efforts to define 802.11n, such as the now dormant Enhanced Wireless Consortium (EWC). The Alliance has upgraded its suite of compatibility tests for some enhancements finalized after draft 2.0. Furthermore, it has affirmed that all draft-n certified products remain compatible with the products conforming to the final standards.[13] The Wi-Fi Alliance is investigating further work on certification of additional features of 802.11n not covered by the Baseline certification, including higher numbers of spatial streams (3 or 4), Greenfield Format, PSMP, Implicit & Explicit Beamforming and Space-Time Block Coding."
