First, which I think is the biggest issue is the discrepancy in cloak visbility when on low or ultra graphics settings. A classes main ability should not be rendered obsolete by graphical settings Please, make the cloak unaffected by graphical settings and always appear like the medium setting.
Should be running a static particle effect like that seen in the old BF 2142. The static effect made it difficult to see at medium to long range but easy at very short range. To compensate for the almost near like invisibility they made it have a discreet noise which could only be heard at very close range.