Isn´t this a win more mechanic? Or perhaps, it breaks stalls... I like the firs better becouse it primary effect helps reaching the condition of the second trigger.
It's about as win-more as ferocious and formidable: It rewards you for something you want to be doing in that color anyhow, sometimes it's just win-more, sometimes it's what you need to pull ahead, or catch up.White is the most likely to fulfill "have 5 creatures" with 1/1s and the like, thanks to its token alignment and creature curve, and so not necessarily winning just because you've got bodies.
The timing on the first design is awkward, because it makes a 1/1 at instant speed but then grants an ability that wants to be played on attacks. You might try "Play ~ only during declare attackers. Put two 1/1 white soldier tokens into play tapped and attacking. If you control 5 or more creatures, creatures you control get +1/+1 until the end of the turn."
+1, was going to say the same thing
Army Trumpet is good on defense, and perfectly usable on offense, but your card is nice too, though no longer common.
I'm not willing to grant that mine can't be common, but it is certainly red flagged, but I think so is yours. Raise the Alarm is still common, and "Raise the Alarm but they enter attacking" would definitely be common. The combo is a weird card and where it went would depend on the set, but I have a hard time imagining a set that wants the card I suggested above where it would not NEED to be common to support a limited archetype. See also: Gearseeker Serpant.
Your card creates two 2/2 haste creatures in addition to boosting the team. That could be a RW common, but not mono-white.
They're only 2/2s for one turn, and yes, I like it a lot more as RW because then you can template it a lot nicelier as having 1/1s with Haste instead of as "entering the battlefield attacking" which is a phrase only a judge could love!