Should be wild plus 567-TJQ.
The increase in EV is insignificant, but the play also decreases variance a
bit. You can increase the EV by learning when to keep just the Deuce, and
when to keep the straight4. Still pretty insignificant, though.
I had an e-mail correspondence with a friend on this subject six years ago,
and he found the result of my Deuce calculations. In hands which contain
an open-ended straight4 with a Deuce, the Deuce alone, on average, is worth
4.9925 coins.
Five shows the EV increase for always holding the straight4, over always
holding the Deuce. Can anyone calculate the EV increase for "perfect play"
on this type of hand, over always holding the Deuce? I'll take a wild guess
and say it's around .002%. Woo again! 
Brian
PS: Here are the complete rules for perfect play on these hands:
Hold the straight4 from W567 unless the fifth card is Q, K, or A
Hold the straight4 from W678 unless the fifth card is 3, A, or a suited K
(suited with either the 6, 7, or 8)
Hold the straight4 from W789 unless the fifth card is 3 or a suited 4
Hold the straight4 from W89T always
Hold the straight4 from W9TJ always
Hold the straight4 from WTJQ unless the fifth card is a 3
···
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In a message dated 4/14/2010 8:24:35 P.M. Pacific Daylight Time,
fivespot55@gmail.com writes:
according to frugal, the expected return of NSUD when you always hold
wild plus ST3 0i (567-89T) over the bare deuce is 99.72585%. the
expected return when you never hold wild four-straights is 99.72522%.
so your chart as printed is a full 0.0006% better than your chart with
your suggested modification, woo.
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