All the P1 guides for Sven are the same these days: Mask of Madness this, Echo Sabre that... Are you guys not tired of it? I am.
So heres my personal, "dirty pleasure" way to play an Alternative Carry Sven, for those who wanna try something different.

Did you know that Sven has a voiceline for building Mordiggian? Probably not, because most people dont build it for him. The general consensus is that only STR heroes with innate lifesteal or other forms of HP regen make it, like Wraith King or Dragon Knight. But Sven is a perfectly viable user for it too, although he does it differently: instead of attempting to compensate for life-drain he simply goes all-in, in an attempt to deal lots of burst damage before he succumbs to it. A moderate risk, high-ish reward playstyle that relies on your team holding enemies down for you to hit them square on the head.

IMPORTANT NOTE: This build is completely countered by Ancient Apparation, and as such you will have to revert to "the old ways" if you spot the icy A-hole on the other side.
It is also ill-advised if enemies stacked up a lot of DoT (Damage over Time) heroes, like Venomancer + Queen of Pain + Earth Spirit, or something among those lines. You can still try it and even pull it off, but you will have to turn the Armlet ON and pray you can kill as many as you can before finally choking on your own lungs.
This also greatly inflates potency of kiting against you, making one of your greatest weaknesses even greater. As i mentioned: you are completely at the mercy of your own team and their ability to hold enemies down. If they cant do it... Well, frankly this usually means you already lost irrelevant of build, but thats a whole other rabbit hole of "why Sven is not a top-tier carry".

Note about Skill leveling: i do not believe that maxing one of your skills to Lv4 ASAP is an optimal strategy. Leveling up your abilities has diminishing returns, and Lv4 is a luxury upgrade with minimal impact in overwhelming amount of cases, with fringe exceptions. Most heroes reach their top performance when they go for 3/3/3 build and not 4/4/1, although it always depends on individual hero and situation at hand. All of that to say: use your head, but when in doubt - it is always a safe bet to attempt to bring your hero fully online rather than attempting to be a one-button pony.