England forward Walcott is on course for a return against former club Southampton at the Emirates Stadium on Saturday having recovered from two months out following minor abdominal surgery.
Wenger is confident Walcott can offer support to lone frontman Olivier Giroud and record signing Mesut Ozil as Arsenal look to respond to defeat at Manchester United to remain top of the Premier League.
"Of course you miss a player like Theo Walcott," said the Arsenal manager.
"Strikers who get behind the defenders is a very important quality and Theo [Walcott] has that quality.
"Theo had a good start to the season, he scored goals, he provided chances and had assists.
"He can always give you a different option in the game and that is of course vital."
Wenger added: "You always want to have a perfect balance [in attack], and if you look at our results our balance was not too bad, but Theo has different qualities to other players and I am very pleased that he is back."
Wenger maintains he has no issue with Jack Wilshere's use by England in the friendlies against Chile and Germany.
The midfielder, who has again been troubled by fitness problems this season, played in both of the internationals at Wembley, where Roy Hodgson's men suffered back-to-back defeats.
Wenger, though, played down any talk of a club-versus-country row.
"First of all Jack is not injured, that was not the right information," Wenger told Arsenal Player.
"Secondly, I have no problem with the FA, they respected completely what they told me and it was (for Wilshere) to play in one game and be on the bench in the other.
"They did that very well, so there is no misunderstanding there. (It was) exactly (what we agreed)."
Czech midfielder Tomas Rosicky could also feature against the high-flying Saints following his illness. Ozil was rested by Germany during the international break to help the former Real Madrid midfielder recover from a sickness bug which had hit the Gunners squad.
German forward Lukas Podolski is, meanwhile, closing in on a return from a hamstring injury which has sidelined him since the end of August.
"He is doing fitness training on the pitch and starts to do some ball work too," said Wenger.
England midfielder Alex Oxlade-Chamberlain remains "at least one month" away from a return after knee ligament damage, while France under-21 forward Yaya Sanogo could be fit from his back problem in January.