A rough nib can be caused by a number of factors.
The width of the nib is always key. An extra-fine or fine nib will always be scratchier than a medium or broad. The Hero pens tend to be mostly extra fines, and they will simply have a scratchier character; even the classic pen it's modelled after, the Parker 51, has scratchier XF nibs than M nibs.
The first one to look at is the "set" of the nib--whether the tines are properly aligned and even. Usually, bending the tines to make them align properly, and not be angled but parallel to each other may be all that's required to get the nib back into good shape. Some people write with pressure in such a way as to disturb the set of the nib, so you may have to repeatedly do this for maintenance. Examining the tines under magnification with a loupe can be useful for this. (See: Richard Binder's nib smoothing workshop notes (PDF)).
A second factor may be the tipping. A fountain pen nib, to write smoothly, should be tipped with a harder material that's been rounded and polished. Cheaper fountain pen nibs may not be tipped, or the tipping may have broken off and left a porous surface. In these cases, using a very fine, mild abrasive surface (like 10,000 grit) to smooth the tipping may work, but can be difficult to do correctly without adding an edge. Light, circular strokes, on a wetted grinding surface may help. Sometimes, the nib may be past this type of repair and may require replacement or retipping.
Inkflow has to do with the air/ink interchange and capillary action. If the pen writes too wetly, drips, or blots a lot, chances are good, the exchange is too heavy. If the pen skips or runs dry a lot, then the exchange is too light. The air/ink exchange is generally controlled by the fit of the nib against the feed (the plastic the nib rests on).
Dried, hardened ink in the feed channels is usually the #1 culprit of a pen that won't start or that skips. Proper fountain pen ink is water-soluable dye. When the water evaporates, the solid pigment can cake and block ink and air passage. A simple soak with water should dissolve the dye, but may take a very long time, depending on how thin the channel is and how accessible it is from soaking. A pen like the Hero is liable to take a good long time (a few days), and will require flushing by filling and emptying the reservoir multiple times. You do not want to soak metal parts (may corrode), and you do not need to use acidic or alkaline solutions (may affect the plastic), and you don't want to soak it in ink because you may pollute fresh ink in the bottle with crud from the old ink (fungus, sediment). Time and water will always clear ink from a fountain pen.
If flushing doesn't help, then the set of the nib against the feed may be the culprit, but it will require disassembly and adjustment, and this is best done by someone who knows how to service the pen.