I often see people complaining about how the Raid Suit gives Sanj too much powers, is just a free power up given by Oda because Sanji is too weak and similar.
With this analysis I want to explain why Oda had always wanted to give a weapon to Sanji from the very beginning and that the powers provided by the Raid Suit are not just random, but Oda planned to give those exact powers to Sanji even before the timeskip.
The first statement is very easy to prove: every Straw Hat has either an ability or a characteristic weapon, and more specifically, the non ability users receive their weapon after their character arc (e.g. Nami takes her iconic clima tact after Arlong Park and Usopp takes kabuto right after Water Seven), with Sanji taking the Raid Suit this pattern is complete!
As for the latter statement I’ll prove it with another pattern specific for Sanji. He always fights the martial artist of the enemy’s crew and later on he acknowledges their techniques.
Baratie: Sanji defeats Pearl who can set himself on fire by rubbing his shields; Sanji uses the friction between his feet and the ground to set his foot ablaze: Diable Jambe.
Arlong Park: Kuroobi and Sanji have an underwater fight focused on the speed of Fishman, Sanji after the timeskip manages to find this speed underwater: Blue Walk.
Enies Lobby: Jabra used Tekkai, which hardened his body (like Sanji’s cape), Geppo (skywalk/Raid Suit flying) and Soru (Sanji’s the fastest in the crew and can achieve disappearing speed just like Soru).
Thriller Bark: Absalom’s invisibility. Raid Suit gave Sanji this power.
In the end the Raid Suit is consistent with how Oda managed Sanji’s ability. A weapon that granted him these powers was in Oda’s mind for at least 13 years.