Szczesny has played brilliant the games he has had and clearly deserved to take Gigis spot long time ago. He has power and a cool attitude. Could not wish for a better keeper now. What more can a GK do than save the saveable shots? Would be a waste of time and money looking for a GK this year IMO.
Regarding Martial - sorry to say, he aint no upgrade on Cuadrado or Costa. Potentially in 2-3 years. Thats not a great investment to make now in our financial situation. Only to replace Dybala/Higuain, or if we get a really good offer on Cuadrado and we want to invest in Martials youth. Unlikely. Lets fix our gaping issues, a shitty midfield where a 20yo Uruguayan currently is bossing the most, and a defence of washed up clumsy and technically inept footballers.